Display device

ABSTRACT

A backlight unit including a frame having a bottom area and a sidewall area extended from the bottom area; a single substrate located in on the bottom area of the frame, a plurality of optical assemblies being mounted on the single substrate; a reflection sheet located the frame and configured to reflect light emitted by the optical assemblies; and an optical sheet located over the reflection sheet. Further, the reflection sheet a first sheet area corresponding to the bottom area of the frame; a second sheet area corresponding to the sidewall area of the frame; and a cut portion cut from the first sheet at one portion abutting on one side of the single substrate.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Continuation of U.S. application Ser. No.15/407,611 filed Jan. 17, 2017, which claims the benefit of KoreanPatent Application No. 10-2016-0007564 filed on Jan. 21, 2016, andKorean Patent Application No. 10-2016-0061420 filed on May 19, 2016 theentire contents of which are incorporated herein by reference for allpurposes as if fully set forth herein.

BACKGROUND OF THE INVENTION Field of the Invention

The present disclosure relates to a display device.

Discussion of the Related Art

With the development of the information society, various demands fordisplay devices are increasing. Various display devices, such as liquidcrystal displays (LCDs), plasma display panels (PDPs),electroluminescent displays (ELDs), and vacuum fluorescent displays(VFDs), have been studied and used to meet various demands for thedisplay devices.

Among the display devices, the liquid crystal display panel of the LCDincludes a liquid crystal layer, and a thin film transistor (TFT)substrate and a color filter substrate disposed to face each other withthe liquid crystal layer interposed therebetween. The liquid crystaldisplay panel displays an image using light provided by the backlightunit of the LCD.

SUMMARY OF THE INVENTION

In accordance with an aspect of the present invention, there can beprovided a backlight unit, including a frame including a bottom area anda sidewall area extended from the bottom area, a single substratelocated in at least one portion on the frame, a plurality of opticalassemblies being mounted on the substrate, a reflection sheet located inat least another portion on the frame, and an optical sheet located overthe reflection sheet, wherein the reflection sheet includes a cutportion, both ends of a portion abutting on one side of the substratebeing cut.

In accordance with another aspect of the present invention, there isprovided a display device, including a frame including a bottom area anda sidewall area extended from the bottom area, a single substratelocated in at least one portion on the frame, a plurality of opticalassemblies being mounted on the substrate, a reflection sheet located inat least another portion on the frame, an optical sheet located over thereflection sheet, and a display panel located over the optical sheet,wherein the reflection sheet includes a cut portion, both ends of aportion abutting on one side of the substrate being cut.

In accordance with yet another aspect of the present invention, therecan be provided an optical lens, including a first surface forming anupper part, a second surface facing the first surface and forming alower part, a third surface connecting the first surface and the secondsurface, and a plurality of lens extension parts extended in an externaldiameter direction of the second surface from some area of the thirdsurface, wherein at least any one of the plurality of lens extensionparts is spaced apart from at least another of the plurality of lensextension parts.

In accordance with another aspect of the present invention, there isprovided a backlight unit, including a frame, a substrate located infront of the frame, a reflection sheet located in front of the at leastone substrate, and an optical assembly disposed on the substrate. Theoptical assembly may include a light source and a lens located on oneside of the light source and including a first surface having a circularsection shape and forming an upper part, a second surface facing thefirst surface and forming a lower part, a third surface connecting thefirst surface and the second surface, and a plurality of lens extensionparts extended in an external diameter direction of the second surfacefrom some area of the third surface. At least one of the plurality oflens extension parts can be spaced apart from at least another of theplurality of lens extension parts.

Further scope of applicability of the present invention will becomeapparent from the detailed description given hereinafter. However, thedetailed description and specific examples, while indicating preferredembodiments of the invention, are given by illustration only, sincevarious changes and modifications within the spirit and scope of theinvention will become apparent to those skilled in the art from thisdetailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention. In the drawings:

FIGS. 1 to 8 are diagrams showing the configuration of a display devicerelated to an embodiment of the present invention.

FIGS. 9 and 10 are diagrams showing a light source according to anembodiment of the present invention.

FIG. 11 is a diagram showing a coupling relation between a reflectionsheet and peripheral elements according to an embodiment of the presentinvention.

FIG. 12 is a diagram showing the configuration of a reflection sheetaccording to an embodiment of the present invention.

FIG. 13 is a diagram showing optical assemblies located on a substrateaccording to an embodiment of the present.

FIGS. 14 to 22 are diagrams showing the configuration of a reflectionsheet according to an embodiment of the present invention.

FIGS. 23 and 24 are diagrams showing a position relation between areflection sheet and peripheral elements according to an embodiment ofthe present invention.

FIG. 25 is a diagram showing the configuration of a reflection sheetaccording to another embodiment of the present invention.

FIGS. 26 to 32 are diagrams showing a dot distribution or stripdistribution of a reflection sheet according to an embodiment of thepresent invention.

FIGS. 33 and 34 are diagrams showing a display device according to anembodiment of the present invention.

FIGS. 35 to 39 are diagrams showing the configuration of a displaydevice related to an embodiment of the present invention.

FIGS. 40 and 41 are diagrams showing a light source according to anembodiment of the present invention.

FIG. 42 is a diagram showing an optical assembly including the lightsources of FIG. 41.

FIGS. 43 and 44 are diagrams showing a difference according to a lensforming an optical assembly.

FIGS. 45 and 46 are diagrams showing a lens according to an embodimentof the present invention.

FIGS. 47 to 51 are diagrams showing the second region of the lens shownin FIG. 45.

FIGS. 52 to 54 are diagrams showing the third surface of the lens shownin FIG. 45.

FIGS. 55 and 56 are diagrams showing the first region of the lens shownin FIG. 45.

FIG. 57 is a diagram showing an example of an optical path according tothe lens of FIG. 45.

FIGS. 58 to 63 are diagrams showing a lens according to otherembodiments of the present invention.

FIGS. 64 and 65 are diagrams showing the deployment of an opticalassembly according to other embodiments of the present invention.

FIGS. 66 to 69 are diagrams showing a lens installed on a substrateaccording to some embodiments of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail embodiments of the inventionexamples of which are illustrated in the accompanying drawings. Sincethe present invention can be modified in various ways and may havevarious forms, specific embodiments are illustrated in the drawings anddescribed in detail in the present specification. However, it should beunderstood that the present invention is not limited to the specificdisclosed embodiments, but may include all modifications, equivalentsand substitutes included within the spirit and technical scope of thepresent invention.

The terms ‘first’ and ‘second’ can be used to describe various elements,but the elements are not limited by such terms. The terms are used onlyfor the purpose of distinguishing one element from other elements. Forexample, a first element can be designated as a second element withoutdeparting from the scope of the present invention. Likewise, a secondelement can be designated as a first element.

The term “and/or” encompasses both combinations of a plurality ofrelated items disclosed and any item of the plurality of related itemsdisclosed. When an arbitrary element is described as “being connectedto” or “being coupled to” another element, this should be understood tomean that still another element(s) may exist between them, although thearbitrary element can be directly connected to, or coupled to, thesecond element. In contrast, when an arbitrary element is described as“being directly connected to” or “being directly coupled to” anotherelement, this should be understood to mean that no element existsbetween them.

The terms used in the present application are used to describe onlyspecific embodiments or examples, and are not intended to limit thepresent invention. A singular expression can include a plural expressionas long as it does not have an apparently different meaning in context.

In the present application, it should be understood that the terms“include” and “have” are intended to designate that illustratedfeatures, numbers, steps, operations, elements, parts or combinationsthereof are present and to not exclude the presence of one or moredifferent features, numbers, steps, operations, elements, parts orcombinations thereof or the possibility of the addition thereof.

Unless otherwise specified, all of the terms which are used herein,including the technical or scientific terms, have the same meanings asthose that are generally understood by a person having ordinaryknowledge in the art to which the present invention pertains. The termsdefined in a generally used dictionary must be understood to havemeanings identical to those used in the context of a related art, andare not to be construed to have ideal or excessively formal meaningsunless they are obviously specified in the present application.

The following embodiments of the present invention are provided to thoseskilled in the art in order to describe the present invention morefully. Accordingly, the shapes and sizes of elements shown in thedrawings may be enlarged, for clarity.

Hereinafter, embodiments of the invention are described by taking aliquid crystal display panel as an example of a display panel. However,other display panels can be used. For example, a plasma display panel(PDP), a field emission display (FED) panel, and an organic lightemitting diode (OLED) display panel can be used.

FIGS. 1 to 10 are diagrams showing the configuration of a display devicerelated to an embodiment of the present invention. As shown in FIG. 1,in the following description, the display device 100 includes a firstlong side LS1, a second long side LS2 facing the first long side LS1, afirst short side SS1 neighboring the first long side LS1 and the secondlong side LS2, and a second short side SS2 facing the first short sideSS1.

The first short side SS1 can be said to be a first side area, and thesecond short side SS2 can be said to be a second side area facing thefirst side area. Also, the first long side LS1 can be said to be a thirdside area neighboring the first side area and the second side area andlocated between the first side area and the second side area. The secondlong side LS2 can be said to be a fourth side area neighboring the firstside area and the second side area, located between the first side areaand the second side area, and facing the third side area.

Furthermore, the first or second long side LS1 or LS2 has beenillustrated as having a longer length than the first or second shortside SS1 or SS2, for convenience of description, but the first or secondlong side LS1 or LS2 may have almost the same length as the first orsecond short side SS1 or SS2.

In the following description, a first direction DR1 can be a directionparallel to the long sides LS1 and LS2 of a display panel 110, and asecond direction DR2 can be a direction parallel to the short sides SS1and SS2 of the display panel 110. Also, a third direction DR3 can be adirection perpendicular to the first direction DR1 and/or the seconddirection DR2.

The first direction DR1 and the second direction DR2 can be collectivelycalled a horizontal direction. Furthermore, the third direction DR3 canbe called a vertical direction. In addition, the side on which thedisplay device 10 displays an image can be said to be the front or thefront surface. When the display device 10 displays an image, the side onwhich the image cannot be seen can be said to be the back or thebackside. When the display device 10 is viewed at the front or the frontsurface, the side of the first long side LS1 can be said to be the upperside or the top. Likewise, the side of the second long side LS2 can besaid to be the lower side or the bottom, the side of the first shortside SS1 can be said to be the left or the left surface, and the side ofthe second short side SS2 can be said to be the right of the rightsurface.

Furthermore, the first long side LS1, the second long side LS2, thefirst short side SS1, and the second short side SS2 can be called theedges of the display device 10. Also, points at which the first longside LS1, the second long side LS2, the first short side SS1, and thesecond short side SS2 meet together can be called corners. For example,a point at which the first long side LS1 and the first short side SS1meet can become a first corner C1, a point at which the first long sideLS1 and the second short side SS2 meet can become a second corner C2, apoint at which the second short side SS2 and the second long side LS2meet can become a third corner C3, and a point at which the second longside LS2 and the first short side SS1 meet can become a fourth cornerC4.

In this instance, a direction from the first short side SS1 to thesecond short side SS2 or a direction from the second short side SS2 tothe first short side SS1 can be said to be a left right direction LR. Adirection from the first long side LS1 to the second long side LS2 or adirection from the second long side LS2 the first long side LS1 can besaid to be an up down direction UD.

As shown in FIG. 2, the display device 100 according to an embodiment ofthe present invention may include a display panel 110 and a back cover150 at the back of the display panel 110. The back cover 150 can beconnected to the display panel 110 in a sliding manner in the directionfrom the first long side LS1 to the second long side LS2, that is, asecond direction DR2. In other words, the back cover 150 can be insertedin a sliding manner from the first short side SS1 of the display panel110, the second short side SS2 facing the first short side SS1, and thefirst long side LS1 neighboring the first and the second short sides SS1and SS2 and located between the first short side SS1 and the secondshort side SS2. In order to connect the back cover 150 to the displaypanel 110 in a sliding manner, a protruding unit, a sliding unit, acoupling part, etc. can be included in the back cover 150 and/or anotherstructure adjacent to the back cover 150.

Next, FIGS. 3 to 7 are diagrams showing the configuration of the displaydevice related to an embodiment of the present invention. As shown inFIG. 3, a display device 100 according to an embodiment of the presentinvention may include a front cover 105, a display panel 110, abacklight unit 120, a frame 130, and a back cover 150.

The front cover 105 may covers at least some area of the front and sideof the display panel 110. The front cover 105 may have a rectangularframe shape having an empty center. Since the center of the front cover105 is empty, an image of the display panel 110 can be displayed to theoutside.

The front cover 105 can be divided into a front cover and a side cover.That is, the front cover 105 can be divided into the front cover placedon the front side of the display panel 110 and the side cover placed onthe side of the display panel 110. The front cover and the side covercan be separately configured. Any one of the front cover and the sidecover may be omitted. For example, the front cover is not present andonly the side cover is present to enhance the beautiful of the design,etc.

The display panel 110 is provided at the front of the display device100, and an image can be displayed on the display panel 110. The displaypanel 110 can divide an image into a plurality of pixels and output theimage according to color, brightness, and chroma for each pixel. Thedisplay panel 110 can be divided into an active area in which an imageis displayed and an inactive area in which an image is not displayed.The display panel 110 also includes a front substrate and a rearsubstrate facing each other with a liquid crystal layer interposedtherebetween.

In particular, the front substrate includes a plurality of pixelsincluding red (R), green (G), and blue (B) subpixels. The frontsubstrate can generate an image corresponding to red, green or bluecolor in response to a control signal. The rear substrate can includeswitching elements. Thus, the rear substrate can switch a pixelelectrode.

For example, the pixel electrode can change the arrangement of themolecules of the liquid crystal layer in response to an external controlsignal. The liquid crystal layer also includes a plurality of liquidcrystal molecules. The arrangement of the liquid crystal molecules arechanged in accordance with a voltage difference generated between thepixel electrode and a common electrode. The liquid crystal layer canalso transfer light, supplied by the backlight unit 120, to the frontsubstrate.

The backlight unit 120 is located at the back of the display panel 110and includes a plurality of light sources. The light source of thebacklight unit 120 can be disposed in a direct type or an edge type. Foran edge type backlight unit 120, a light guide panel is included.

The backlight unit 120 can be coupled to the front of the frame 140. Forexample, the plurality of light sources can be disposed on the frontside of the frame 140. In such a case, the backlight unit 120 iscommonly called a direct type backlight unit.

The backlight unit 120 can be driven using a total driving method or apartial driving method, such as local dimming or impulsive. Thebacklight unit 120 may also include an optical sheet 125 and an opticallayer 123. The optical sheet 125 enables light of the light source to beuniformly delivered to the display panel 110 and may include a pluralityof layers. For example, the optical sheet 125 may include at least oneprism sheet and/or at least one diffusion sheet.

In addition, the optical sheet 125 may include at least one couplingpart 125 d. The coupling part 125 d can be coupled to the front cover105 and/or the back cover 150. That is, the coupling part 125 d can bedirectly coupled to the front cover 105 and/or the back cover 150.Alternatively, the coupling part 125 d can be coupled to a structurecoupled to the front cover 105 and/or the back cover 150. That is, thecoupling part 125 d can be indirectly coupled to the front cover 105and/or the back cover 150. The optical layer 123 may include the lightsource and so on. The optical layer 123 is described in detail in acorresponding part.

The frame 130 functions to support elements of the display device 100.For example, an element, such as the backlight unit 120, can be coupledto the frame 130. The frame 130 can be made of a metallic material, suchas an aluminum alloy. The back cover 150 can be located at the backsideof the display device 100. The back cover 150 also protects internalelements from the outside. At least some of the back cover 150 can becoupled to the frame 130 and/or the front cover 105. The back cover 150can also be an injected matter made of resin.

Next, FIG. 4 is a diagram showing elements, such as the optical sheet125. As shown in FIG. 4(a), the optical sheet 125 and/or a diffusionplate 129 can be located above the frame 130. The optical sheet 125and/or the diffusion plate 129 can be coupled to the frame 130 at theedge of the frame 130. The optical sheet 125 and/or the diffusion plate129 can be directly seated in the edge of the frame 130. That is, theouter circumference of the optical sheet 125 and/or the diffusion plate129 can be supported by the frame 130. The upper surface of the edge ofthe optical sheet 125 and/or the diffusion plate 129 can be surroundedby a first guide panel 117. For example, the optical sheet 125 and/orthe diffusion plate 129 can be located between the edge of the frame 130and the flange 117 a of the first guide panel 117.

The display panel 110 can be located on the front side of the opticalsheet 125, and the edge of the display panel 110 can be coupled to thefirst guide panel 117. That is, the display panel 110 can be supportedby the first guide panel 117. In addition, the edge area of the front ofthe display panel 110 can be surrounded by the front cover 105. Forexample, the display panel 110 can be located between the first guidepanel 117 and the front cover 105.

As shown in FIG. 4(b), the display device 100 according to an embodimentof the present invention may further include a second guide panel 113.The optical sheet 125 and/or the diffusion plate 129 can be coupled tothe second guide panel 113. That is, the second guide panel 113 can becoupled to the frame 130 and the optical sheet 125 and/or the diffusionplate 129 can be coupled to the second guide panel 113. The second guidepanel 113 can be made of a material different from that of the frame130. The frame 130 may have a form that surrounds the first and thesecond guide panels 117 and 113.

As shown in FIG. 4(c), in the display device 100 according to anembodiment of the present invention, the front cover 105 may not coverthe front of the display panel 110. That is, one end of the front cover105 can be located on the side of the display panel 110.

Referring to FIGS. 5 and 6, the backlight unit 120 includes a substrate122, at least one optical assembly 124, the optical layer 123 includinga reflection sheet 126 and a diffusion plate 129, and the optical sheet125 located on the front side of the optical layer 123. The substrate122 may have a plurality of strip forms extended in the first directionand spaced apart from each other at a specific interval in the seconddirection orthogonal to the first direction. At least one opticalassembly 124 can be mounted on the substrate 122. An electrode patternfor connecting an adapter and the optical assembly 124 can be formed onthe substrate 122. For example, a carbon nanotube pattern for connectingthe optical assembly 124 and the adapter can be formed on the substrate122.

The substrate 122 can be made of at least one of polyethyleneterephthalate (PET), glass, polycarbonate (PC), and silicon. Thesubstrate 122 can be a printed circuit board (PCB) on which at least oneoptical assembly 124 is mounted. In addition, the optical assembly 124can be disposed on the substrate 122 at a specific interval in the firstdirection. The diameter of the optical assembly 124 can be greater thanthe width of the substrate 122. That is, the diameter of the opticalassembly 124 can be greater than the length of the substrate 122 in thesecond direction.

The optical assembly 124 can be a light-emitting diode (LED) chip or alight-emitting diode package including at least one LED chip. Further,the optical assembly 124 may include a colored LED that emits at leastone of red, blue, and green or a white LED. The colored LED may includeat least one of a red LED, a blue LED, and a green LED.

The light source included in the optical assembly 124 can be a chip onboard (COB) type. The COB type may have a form in which an LED chip,that is, a light source, has been directly coupled to the substrate 122.Accordingly, the process can be simplified. Furthermore, resistance canbe lowered, thereby being capable of reducing energy lost due to heat.That is, power efficiency of the optical assembly 124 can be improved.The COB type can provide brighter lighting and can be implemented thinand light compared to a related art technology.

In addition, the reflection sheet 126 can be located on the front sideof the substrate 122. The reflection sheet 126 can also be located on anarea other than the area in which the optical assembly 124 of thesubstrate 122 has been formed. That is, a plurality of through holes 235can be formed in the reflection sheet 126.

The reflection sheet 126 reflects light, emitted from the opticalassembly 124, toward the front side. Furthermore, the reflection sheet126 reflects light, reflected by the diffusion plate 129, again. Thereflection sheet 126 may include at least one of metal and metal oxide,that is, reflection materials. For example, the reflection sheet 126 mayinclude metal and/or metal oxide having high reflectance, such as atleast one of aluminum (Al), silver (Ag), gold (Au), and titanium dioxide(TiO2).

In addition, the reflection sheet 126 can be formed by depositing and/orcoating metal or metal oxide on the substrate 122. Ink including ametallic material can be printed on the reflection sheet 126. Adeposition layer using a vacuum deposition method, such as a thermaldeposition method, an evaporation method or a sputtering method, can beformed in the reflection sheet 126. Also, a coating layer and/or a printlayer using a printing method, a gravure coating method or a silk screenmethod can be formed in the reflection sheet 126.

An air gap can be located between the reflection sheet 126 and thediffusion plate 129. The air gap can function as a buffer capable ofwidely spreading light emitted from the optical assembly 124. In orderto maintain the air gap, a supporter 200 can be located between thereflection sheet 126 and the diffusion plate 129.

In addition, resin can be deposited on the optical assembly 124 and/orthe reflection sheet 126. The resin functions to spread light emittedfrom the optical assembly 124. Also, the diffusion plate 129 spreadslight emitted from the optical assembly 124 to the upper part.

The optical sheet 125 can be located on the front side of the diffusionplate 129, the backside of the optical sheet 125 can closely adhere tothe diffusion plate 129, and the front surface of the optical sheet 125can closely adhere to the backside of the display panel 110. Inaddition, the optical sheet 125 may include at least one or more prismsheets and/or one or more diffusion sheets. The plurality of sheetsincluded in the optical sheet 125 can be in an adhesion and/or closeadhesion state.

The optical sheet 125 may also include a plurality of sheets havingdifferent functions. For example, the optical sheet 125 may includefirst to third optical sheets 125 a to 125 c. The first optical sheet125 a may have a function of a diffusion sheet, and the second and thethird optical sheets 125 b and 125 c may have a function of a prismsheet. The number and/or location of the diffusion sheet and the prismsheet can be changed. For example, the optical sheet 125 may include thefirst optical sheet 125 a, that is, a diffusion sheet, and the secondoptical sheet 125 b, that is, a prism sheet.

The diffusion sheet can make luminance of light more uniformly bypreventing light emitted from the diffusion plate from being partiallyconcentrated. The prism sheet can condense light emitted from thediffusion sheet so that the light is vertically incident on the displaypanel 110.

The coupling part 125 d can also be formed in at least one of the edgesof the optical sheet 125. The coupling part 125 d can be formed in atleast one of the first to the third optical sheets 125 a to 125 c.Further, the coupling part 125 d can be formed in an edge on thelong-side side of the optical sheet 125. The coupling part 125 d formedon the first long-side side and the coupling part 125 d formed on thesecond long-side side can be asymmetric. For example, the locationand/or number of coupling parts 125 d on the first long-side side andthe location and/or number of coupling parts 125 d on the secondlong-side side can be different.

Referring to FIG. 7(a), the substrate 122, including a plurality ofstrips extended in the first direction and spaced apart from each otherat a specific interval in the second direction orthogonal to the firstdirection, can be provided on the frame 130. Ends on one side of theplurality of substrates 122 can be connected to a wiring electrode 232.

The wiring electrode 232 can be extended in the second direction andconnected to the ends on one side of the substrates 122 at a specificinterval in the second direction. A wiring hole 234 can be formed at anend on one side of the wiring electrode 232. The wiring hole 234 can bea minute hole penetrates the frame 130 and extended to the back of theframe 130 through the wiring hole 234. The wiring electrode 232 can beelectrically connected to an adapter, located at the back of the frame130, through the wiring hole 234.

Further, the optical assemblies 124 can be mounted on the substrate 122at a specific interval in the first direction. The diameter of theoptical assembly 124 can be greater than the width of the substrate 122in the second direction. Accordingly, the outside area of the opticalassembly 124 can be over an area in which the substrate 122 is notprovided.

Referring to FIG. 7(b), a substrate 122 including a plurality of stripscan be extended in a different direction other than the first directionat both ends. That is, both ends of the substrate 122 can be extended toan edge area so that the optical assemblies 124 are located in the edgearea. The dark part of the edge area can be compensated for because thesubstrate 122 on which the optical assemblies 124 have been mounted islocated in the edge area. That is, the entire area of the display devicecan emit light uniformly.

An end on one side of the substrate 122 located in the edge area can beconnected to the wiring electrode 232. The wiring electrode 232 can beextended in the second direction, and can be electrically connected tothe adapter located at the back of the frame 130 through the wiring hole234 formed at an end on one side thereof.

Referring to FIG. 8, the wiring electrode 232 extended from the front ofthe frame 130 can be connected to one side of a power supply 315 throughthe wiring hole 234. The power supply 315 can be a printed circuit boardfor supplying power to the display device 100. The power supply 315 maychange an AC frequency into a DC frequency. That is, the power supply315 can change a low frequency into a high frequency, thereby beingcapable of improving electrical efficiency.

The power supply 315 can enable the optical assembly 124, located at thefront of the frame 130, to emit light through the wiring electrode 232.The power supply 315 can be connected to a main board 321 through thewiring electrode 232 on the other side. The main board 321 is spacedapart from the power supply 315 at a specific interval. For example, themain board 321 and the power supply 315 can be located to face eachother in the second direction based on the central part of the frame130.

The main board 321 can be a printed circuit board that provides aninterface in which the display device 100 operates. Furthermore, themain board 321 can check and manage the operating state of each of theelements of the display device 100. The main board 321 and the powersupply 315 can be connected to the T-CON board 319 through the wiringelectrode 232. The T-CON board 319 can be a printed circuit board thattransfers a signal, received from the main board 321 or the power supply315, to the display panel 110.

The T-CON board 319 can be electrically connected to the display panel110 at the front of the frame 130 through a flat flex cable (FFC) 251.The printed circuit boards have been illustrated as being connected, butthe present invention is not limited thereto. Only at least some of theprinted circuit boards can be connected.

Next, FIGS. 9 and 10 are diagrams showing a light source according to anembodiment of the present invention. As shown in FIG. 9, the lightsource 203 can be a COB type including at least one of a light emissionlayer 135, first and second electrodes 147 and 149, and a fluorescentlayer 137.

The light emission layer 135 can be located the substrate 122. The lightemission layer 135 may emit light of any one of blue, red, and green.The light emission layer 135 may include any one of Firpic,(CF3ppy)2Ir(pic), 9, 10-di 2-naphthyl)anthracene(AND), Perylene,distyrybiphenyl, PVK, OXD-7, and UGH-3(Blue) and a combination of them.The first and the second electrodes 147 and 149 can be located on bothsides of the bottom of the light emission layer 135. The first and thesecond electrodes 147 and 149 can transfer an external driving signal tothe light emission layer 135.

The fluorescent layer 137 covers the light emission layer 135 and thefirst and the second electrodes 147 and 149. The fluorescent layer 137may include a fluorescent material that converts light of a spectrum,generated by the light emission layer 135, in white light. The lightemission layer 135 may have a uniform thickness on the fluorescent layer137. The fluorescent layer 137 may have a refractive index of 1.4 to2.0.

The light source 203 of a COB type according to an embodiment of thepresent invention can be directly mounted on the substrate 122.Accordingly, the size of the optical assembly 124 can be reduced. Thelight source 203 can be driven with a high current due to excellentradiation because it is located on the substrate 122. Accordingly, thenumber of light sources 203 necessary to secure the same amount of lightcan be reduced. A wire bonding process may also not be required becausethe light source 203 is mounted on the substrate 122. Accordingly, acost can be reduced because the process is simplified.

As shown in FIG. 10, the emission of the light source 203 according toan embodiment of the present invention can be performed in a first lightemission area EA1. That is, light emission can be performed in an areaincluding a second light emission area EA2, that is, the front side, andthird and fourth light emission areas EA3 and EA4, that is, the sides.Such a point is different from a point that a related art light sourceincluding the POB type emits light in the second light emission areaEA2. That is, the light source 203 according to an embodiment of thepresent invention can be a light source of a COB type that can emitlight in a wide range including the sides.

It is preferable to effectively control light in the side directionbecause the light source 203 of a COB type emits light in the sidedirection corresponding to the second light emission area EA2. Thereflection sheet according to an embodiment of the present invention cancontrol reflectance of light emitted in the side direction of the lightsource 203. Accordingly, the irregularity of luminosity attributable tolight in the side direction can be reduced.

FIG. 11 is a diagram showing a coupling relation between a reflectionsheet and peripheral elements according to an embodiment of the presentinvention. As shown in FIG. 11, the reflection sheet 126 according to anembodiment of the present invention can be seated in the frame 130. Forexample, the reflection sheet 126 can be coupled to a seated part 132formed inside the frame 130.

A horizontal coupling part HH and/or a vertical coupling part VH can beformed in the reflection sheet 126. For example, coupling holes can beformed in some areas along the long side and/or short side of thereflection sheet 126. The horizontal coupling part HH and/or thevertical coupling part VH can be inserted into a horizontal protrusion130H and/or a vertical protrusion 130V formed in the frame 130. A guidepanel GP can also be coupled to the reflection sheet 126.

The guide panel GP can be made of injected plastic or press-processedmetal and be coupled to the horizontal protrusion 130H and/or thevertical protrusion 130V. When the guide panel GP is coupled to thereflection sheet 126, the reflection sheet 126 can be fixed between theframe 130 and the guide panel GP. In FIG. 11, the guide panels GP havebeen illustrated as being separated along the long side and the shortside, but may have the long-side side and the short-side side coupledtogether.

The reflection sheet 126 seated in the frame 130 may have a stereoscopicshape corresponding to a shape of the seated part 132. The reflectionsheet 126 according to an embodiment of the present invention canimplement an optimum reflection effect although it has the stereoscopicshape. For example, light can be uniformly reflected over the entirereflection sheet 126.

The reflection sheet 126 forms part of the backlight unit (120 of FIG.5). Further, the substrate 122 on which the light source 203 has beenmounted can be formed between the reflection sheet 126 and the frame130. In the display device according to an embodiment of the presentinvention, a single substrate 122 can be extended and disposed in thefirst direction. Since a single substrate 122 is configured, the numberof optical assemblies 124 for the display device is reduced, therebybeing capable of reducing a manufacturing cost. Furthermore, since asingle substrate 122 is configured, the uniformity of light can befurther improved compared to when a plurality of the substrates 122 isconfigured. The substrate 122 can be connected to a signal line 121connected to the control unit of the display device 100. The signal line121 can be connected to the substrate 122 through a through hole formedin the frame 130.

A coupling hole 317 can be formed in a portion that belongs to thereflection sheet 126 and that corresponds to the substrate 122. Forexample, the coupling hole 317 can be extended and formed in the firstdirection in such a way as to correspond to the substrate 122.

The reflection sheet 126 may include a plurality of supporter holes 205.The supporter 200 can be coupled to the supporter hole 205 and cansupport the diffusion plate 129 and/or the optical sheet 125 formed atthe front of the reflection sheet 126. That is, the reflection sheet 126and the diffusion plate 129 and/or the optical sheet 125 can be spacedapart from each other at a specific interval.

FIG. 12 is a diagram showing the configuration of a reflection sheetaccording to an embodiment of the present invention. As shown in FIG.12, in the display device according to an embodiment of the presentinvention, the reflection sheet 126 may include a first sheet area 126 aand a second sheet area 126 b. The first sheet area 126 a can be locatedin a portion corresponding to the seated part (132 of FIG. 11) withinthe frame 130. When coupled to the frame 130, the first sheet area 126 acan be changed in accordance with a shape within the frame 130. That is,the first sheet area 126 a can be extended in the horizontal direction.

The second sheet area 126 b can be located in a portion corresponding tothe sidewall area of the frame 130. Like the sidewall area of the frame130, the second sheet area 126 b can be formed to be parallel to the Zdirection or obliquely inclined in the Z direction.

In the display device according to an embodiment of the presentinvention, the width of the seated part within the frame 130 having thesubstrate 122 located therein may not be great because a singlesubstrate 122 is configured. Accordingly, the width BA of the firstsheet area 126 a in the second direction, corresponding to the seatedpart (132 of FIG. 11) within the frame 130, can be smaller than thesecond direction width CA of the second sheet area 126 b.

FIG. 13 is a diagram showing optical assemblies located on a substrateaccording to an embodiment of the present. As shown in FIG. 13, theoptical assembly 124 can be disposed on the substrate 122. The opticalassembly 124 includes the light source 203 and a lens 300. The lens 300can be mounted on a substrate groove SD formed in the substrate 122.

As shown in FIG. 13(a), in the existing optical assembly 124, the lenses300 may have the same or similar diameters in all parts. That is, in theexisting lens 300, a diameter SR1 in the first direction and a diameterLR1 in the second direction can be the same or similar.

The diameter of the lens 300 can be greater than the width of thesubstrate 122 in the second direction. Accordingly, the lens 300 can beprotruded from the substrate 122 by a first length PD1 in the seconddirection. In the case of a related art display device, the first lengthPD1 can be short because the diameter of the lens 300 is the same orsimilar in all of parts.

As shown in FIG. 13(b), in the display device according to an embodimentof the present invention, the diameter of the lens 300 can be differentdepending on a location. For example, the diameter SR2 of the lens 300in the first direction can be shorter than the diameter LR2 of the lens300 in the second direction. That is, the lens 300 of the display deviceaccording to an embodiment of the present invention can be oval.

In the display device according to an embodiment of the presentinvention, the lens 300 can be protruded from the substrate 122 by asecond length PD2. The lens 300 may have a greater diameter in thesecond direction. Accordingly, the lens 300 can be further protrudedfrom the substrate 122 in the second direction. Accordingly, the secondlength PD2 can be longer than the first length PD1.

FIGS. 14 to 22 are diagrams showing the configuration of a reflectionsheet according to an embodiment of the present invention. As shown inFIG. 14, in the display device according to an embodiment of the presentinvention, the optical assembly 124 may have an oval shape. For example,the diameter of the optical assembly 124 in the second direction can begreater than that in the first direction. Accordingly, the range of theoptical assembly 124 in which light is emitted in the second directioncan be great compared to an existing optical assembly.

Accordingly, although only a single substrate 122 on which the opticalassembly 124 has been mounted is configured, emitting light can reach upto the edge of the display device in the second direction stronger.Accordingly, although a single substrate 122 is configured, the displaydevice can maintain light uniformity.

As shown in FIG. 15, in the display device according to an embodiment ofthe present invention, the reflection sheet 126 may include a cutportion 159. The cut portion 159 can be a portion cut from thereflection sheet 126 and located at both ends of the substrate 122 onone side thereof in the second direction. The reflection sheet 126 canbe separated or brought into contact with each other using the cutportion 159.

The cut portion 159 can be located on the first sheet area 126 a of thereflection sheet 126. The cut portion 159 helps the first sheet area 126a to be inserted into the substrate 126. If the cut portion 159 extendsto the second sheet area 126 b, the shape of a boundary portion of thefirst sheet area 126 a and the second sheet area 126 b can be modified.Accordingly, the cut portion 159 is preferably located on the firstsheet area 126 a only.

As shown in FIG. 16, the cut portion 159 can be extended in a directioninclined from the first direction at a specific angle IA. Accordingly,the distance between the cut portions 159 can be reduced as the cutportion 159 becomes distant from the substrate 122 in the seconddirection. In this instance, as the cut portion 159 becomes distant fromthe substrate 122, the cut portion 159 can be formed inside the firstsheet area 126 a. Accordingly, the possibility that the shape of aboundary portion between the first sheet area 126 a and the second sheetarea 126 b may be deformed by the cut portion 159 can be reduced.

One end of the cut portion 159 can be located at an edge in the firstdirection compared to the optical assembly 124 located on the outmostside. More specifically, the extension line IL of a portion where thecut portion 159 and the substrate 122 come into contact with each othercan be more located on the outside than the extension line OLL of theoptical assembly 124 located on the outmost side.

If the portion where the cut portion 159 and the substrate 122 come intocontact with each other is more located on the inside than the opticalassembly 124 located on the outmost side, the reflection sheet 126 maynot be inserted into the optical assembly 124 that is more located onthe outside than the cut portion 159. Accordingly, the portion where thecut portion 159 and the substrate 122 come into contact with each othercan be more located at an edge than the optical assembly 124 located onthe outmost side.

As shown in FIG. 17(a), the cut portion 159 can be inclined at a rightangle to the first direction and extended. That is, although the cutportion 159 becomes distant from the substrate 122, the distance betweenthe cut portions 159 can be constant. In this instance, there is anadvantage in that the durability of the reflection sheet can be furtherenhanced because the width between the cut portions 159 is constant.

As shown in FIG. 17(b), the extension line IL extended from the cutportion 159 in the second direction can be more located on the outerside than the extension line SL of one end of the substrate 122. Thatis, the width of the reflection sheet 126 separated by the cut portion159 in the first direction can be greater than that of the substrate 122in the first direction. In this instance, since the width of thereflection sheet 126 is great, the reflection sheet 126 can be furtherconveniently inserted into the substrate 122.

As shown in FIG. 17(c), the cut portion 159 can be inclined from thefirst direction at an angle of 90 degrees or more. That is, as the cutportion 159 becomes distant from the substrate 122 in the seconddirection, the distance between the cut portions 159 can be increased.In this instance, the reflection sheet 126 can be further convenientlyinserted into the substrate 122 because the distance between the cutportions 159 is increased as the cut portion 159 becomes distant fromthe substrate 122.

The shape of the cut portion 159 is not limited to those shown in thedrawings. The cut portion 159 may have a different shape if a lineextended from the cut portion 159 in the second direction is morelocated on the outside than the extension line of the optical assembly124 located on the outmost side.

As shown in FIG. 18, in order to insert one reflection sheet 126 intothe bottom of the optical assembly 124, first, the reflection sheet 126can be inserted into the other reflection sheet 126 on the side oppositethe cut portion. In this instance, one reflection sheet 126 in one partwhere the cut portion is located can be separated from the otherreflection sheet 126 in the other part.

Next, the upper surface RSF of the reflection sheet 126 where the cutportion has been located can be inserted to come into contact with thelower surface LBS of the optical assembly 124. First, the upper surfaceRSF at the end of the reflection sheet 126 can be bent so that it entersunder the lower surface LBS of the optical assembly 124. The bent oneend of the reflection sheet 126 can be pushed in so that the lowersurface LBS of the optical assembly 124 and the upper surface RSF of thereflection sheet 126 come into contact with each other. The reflectionsheet 126 may not be easily separated from the optical assembly 124after it is inserted because the lower surface LBS of the opticalassembly 124 presses the upper surface RSF of the reflection sheet 126.

As shown in FIG. 19(a), an existing display device may include a lenshole 235 in a portion where the reflection sheet 126 corresponds to theoptical assembly 124. In this instance, after the optical assembly 124is made to correspond to the lens hole 235, the reflection sheet 126 canbe covered and coupled.

In this instance, at least part of the optical assembly 124 can beprotruded from the substrate 122 because the diameter of the opticalassembly 124 is greater than the width of the substrate 122. In thisinstance, the protruded portion may not be covered with the reflectionsheet 126 due to the lens hole 235. That is, the frame 130 can beexposed upward due to the protruded portion. Accordingly, a dark partcan be formed by the exposed frame 130. In this instance, light emittedfrom the backlight unit may not be uniform.

In contrast, as shown in FIG. 19(b), in the display device according toan embodiment of the present invention, the reflection sheet 126 can beinserted into the lower part of the optical assembly 124. Accordingly,the frame 130 is not exposed to the outside. In this instance, a darkpart is not formed because light is reflected by the reflection sheet126 or the substrate 122 in the entire portion. That is, light emittedfrom the backlight unit can be uniform.

Referring to FIG. 20, since the light source is located at the centralpart of the optical assembly 124, a bright point can be formed at aportion where the optical assembly 124 is located. Accordingly, it isnecessary to reduce the amount of light reflected from the portion wherethe optical assembly 124 is located. Accordingly, a compensation hole271 can be formed in the lower surface of the optical assembly 124protruded from the substrate 122. In the portion where the compensationhole 271 has been formed, the frame 130 can be exposed to the outside.Accordingly, the amount of reflected light can be reduced.

As shown in FIG. 20(a), the compensation hole 271 of a rectangular shapecan be located at the portion where the reflection sheet 126 and thesubstrate 122 come into contact with each other. As shown in FIGS. 20(b)and 20(c), the compensation hole 271 is located at the portion where thereflection sheet 126 and the substrate 122, but the width of thecompensation hole 271 in the second direction can be increased towardthe central part of the optical assembly 124 in the first direction.

The display device according to an embodiment of the present inventioncan adjust the uniformity of light emitted from the backlight unitbecause the compensation hole 271 is formed in the lower surface of theoptical assembly 124. Accordingly, a bright point or a dark point maynot be formed on a display screen.

As shown in FIG. 21(a), a horizontal bending line HBL and a verticalbending line VBL can be located in the reflection sheet 126. Thehorizontal bending line HBL and the vertical bending line VBL maycorrespond to the boundary of the first sheet area 126 a and the secondsheet area 126 b. When the reflection sheet 126 is coupled to the frame130, the first sheet area 126 a and the second sheet area 126 b can beseparated by folding the horizontal bending line HBL and the verticalbending line VBL. For example, the first sheet area 126 a can be locatedinside the horizontal bending line HBL and the vertical bending lineVBL, and the second sheet area 126 b can be located outside thehorizontal bending line HBL and the vertical bending line VBL.

The horizontal bending line HBL may include a dash area DL and a centerarea JL. The dash area DL can be an area that belongs to the horizontalbending line HBL and in which a hole has been formed. As the size of thedash area DL increases, the horizontal bending line HBL can be foldedmore easily. The center area JL can be an area that belongs to thehorizontal bending line HBL and in which a hole has not been formed. Asthe size of the center area JL increases, shapes on both sides of thehorizontal bending line HBL remain intact although the horizontalbending line HBL is folded.

The dash area DL and the center area JL can be alternately located. Inthe horizontal bending line HBL, the dash area DL and the center area JLmay have a ratio of 1:1. That is, the dash areas DL may have a constantwidth and the center areas JL may also have a constant width. Althoughonly the contents related to the horizontal bending line HBL have beenillustrated, the vertical bending line HBL may have the sameconfiguration as the horizontal bending line HBL.

As shown in FIG. 21(b), the reflection sheet 126 may include the firstto third sheet areas 126 a to 126 c. The first sheet area 126 a and thesecond sheet area 126 b can be divided by the horizontal bending lineHBL or the vertical bending line VBL. That is, the first sheet area 126a and the second sheet area 126 b can be folded using the horizontalbending line HBL or the vertical bending line VBL. Accordingly, thefirst sheet area 126 a and the second sheet area 126 b can be extendedin different directions.

In this instance, the second sheet area 126 b can be naturally changedin accordance with a shape of the frame 130. That is, a naturallyrounded second sheet area 126 b can be formed. Accordingly, there is anadvantage in that workability can be improved because a separate processfor forming the chamfer of the reflection sheet 126 is not required.

As the ratio of the dash area DL decreases, tensile stress between thefirst sheet area 126 a and the second sheet area 126 b may furtherincrease. In this instance, one end of the first sheet area 126 a can beseparated from the bottom area of the frame 130 at a first interval HD1by the second sheet area 126 b. That is, the first sheet area 126 a canbe lifted off from the bottom area of the frame 130 by the tensile forceof the second sheet area 126 b.

In another embodiment, as shown in FIG. 22(a), in the horizontal bendingline HBL, a ratio of the dash area DL and the center area JL can bedifferent. The width of the dash area DL per unit area can be greaterthan that of the center area JL per unit area. For example, the dasharea DL can be located in a dashed dotted line form. That is, the dasharea DL having a great width and the dash area DL having a small widthcan be alternately located.

As shown in FIG. 22(b), since the width of the dash area DL per unitarea is greater than that of the center area JL, one end of the firstsheet area 126 a can be separated from the bottom area of the frame 130at a second interval HD2 by the second sheet area 126 b. The secondinterval HD2 can be smaller than the first interval (HD1 of FIG. 21).That is, the degree to which the first sheet area 126 a is lifted offfrom the bottom area of the frame 130 can be smaller. The backlight unitcan emit light more uniformly because the degree to which the firstsheet area 126 a of the reflection sheet 126 is lifted off is small.

Next, FIGS. 23 and 24 are diagrams showing a position relation between areflection sheet and peripheral elements according to an embodiment ofthe present invention. As shown in FIG. 23(a), an existing displaydevice has a structure in which the substrate 122 is covered with thereflection sheet 126. Accordingly, the height of a portion to which theoptical assembly 124 is adjacent is different. That is, at least some oflight emitted to the side of the optical assembly 124 is reflected bythe side of the reflection sheet 126.

Accordingly, as shown in FIG. 23(a), a bright point can be formed at aportion where the optical assembly 124 is located due to light reflectedby the side of the reflection sheet 126. In contrast, as shown in FIG.23(b), the display device according to an embodiment of the presentinvention has a structure in which the reflection sheet 126 is insertedinto the side of the substrate 122. Accordingly, the height of thebottom area can be constant in any portion. In this instance, as shownin FIG. 23(b), light emitted to the side of the optical assembly 124 canbe spread without being hindered. Accordingly, the backlight unit canemit light more uniformly.

As shown in FIG. 24(a), the existing display device has a structure inwhich the substrate 122 is covered with the reflection sheet 126.Accordingly, in a portion where the substrate 122 is not located, thereflection sheet 126 can be lifted off from the frame 130. In thisinstance, the reflection sheet 126 can be subsided toward the frame 130as it becomes distant from the substrate 122. That is, the height of thereflection sheet 126 can be decreased as it becomes distant from thesubstrate 122. Accordingly, the backlight unit may not emit lightuniformly because the reflection sheet 126 does not emit lightuniformly.

In contrast, as shown in FIG. 24(b), the display device according to anembodiment of the present invention has a structure in which thereflection sheet 126 is inserted into the side of the substrate 122.Accordingly, the reflection sheet 126 can come into contact with theframe 130. That is, the height of the reflection sheet 126 can be thesame regardless of a location. Accordingly, the backlight unit can emitlight uniformly because the reflection sheet 126 reflects lightuniformly.

FIG. 25 is a diagram showing the configuration of a reflection sheetaccording to another embodiment of the present invention. As shown inFIG. 25, in the display device according to an embodiment of the presentinvention, the cut portions 159 can be located on both sides of thesubstrate 122 in the second direction. The cut portion 159 may include afirst cut portion 159 a located on the upper side of the substrate inthe second direction and a second cut portion 159 b located on the lowerside of the substrate in the second direction. The first cut portion 159a and the second cut portion 159 b have been illustrated as having asymmetrical shape based on the substrate 122, but are not limitedthereto. The first cut portion 159 a and the second cut portion 159 bmay have different shapes.

In the display device according to an embodiment of the presentinvention, the cut portions 159 can be located on both sides of thesubstrate 122 in the second direction. Accordingly, both the first andthe second cut portions 159 a and 159 b can be open and the reflectionsheet 126 can be inserted into the side of the substrate 122.Accordingly, the reflection sheet 126 can be assembled more easily.

FIGS. 26 to 32 are diagrams showing a dot distribution or stripdistribution of a reflection sheet according to an embodiment of thepresent invention. As shown in FIG. 26, the frame 130 may include firstto third frame areas 130 a to 130 c. The first frame area 130 a can bethe bottom area of the frame 130, and can be substantially flat. Thatis, the first frame area 130 a can be a surface located on the X-Y planeof the display device 100.

The second frame area 130 b can be a sidewall area extended upward fromthe first frame area 130 a. The second frame area 130 b may have adirection parallel to the Z direction or a direction obliquely inclinedwith respect to the Z direction. Further, the seated part (132 of FIG.10) can be formed within the frame 130 by the second frame area 130 bthat functions as the sidewall of the frame 130.

The third frame area 130 c can be an area extended from the second framearea 130 b in the X direction and can be substantially parallel to thefirst frame area 130 a. That is, the third frame area 130 c has heightdifferent from that of the first frame area 130 a due to the secondframe area 130 b, but may have a flat surface like the first frame area130 a.

A protruded area can be present in the third frame area 130 c. Aprotrusion formed by a separate process can be coupled to the thirdframe area 130 c. The reflection sheet 126 can be coupled to theprotruded area and/or protrusion of the third frame 130 c. For example,the third sheet area 130 c of the reflection sheet 126 can be coupled tothe protruded area and/or protrusion. The optical sheet (215 of FIG. 5)can be coupled to the protruded area and/or protrusion of the thirdframe 130 c.

The reflection sheet 126 can be coupled to the area formed by the firstto the third frame areas 130 a to 130 c. When the reflection sheet 126and the frame 130 are coupled together, the shape of the reflectionsheet 126 can be naturally changed in accordance with a shape of theframe 130. That is, a naturally rounded second sheet area 126 b can beformed. Accordingly, there is an advantage in that workability can beimproved because a separate process for forming the chamfer of thereflection sheet 126 is not required.

The reflection sheet 126 may include the first to the third frame areas126 a to 126 c. That is, the area of the reflection sheet 126 can bedivided depending on whether the reflection sheet 126 and the frame 130come into contact with each other or not. For example, the reflectionsheet 126 is divided into a contact area where the reflection sheet 126and the frame 130 come into contact with each other and a non-contactarea where the reflection sheet 126 and the frame 130 do not come intocontact with each other.

The first and the second sheet areas 126 a and 126 b can be divided bythe horizontal bending line HBL. In other words, the second sheet area126 b can be an area coming into contact with the third frame area 130 cin the horizontal bending line HBL. The first and the second sheet areas126 a and 126 b can be divided depending on whether they come intocontact with the first region 130 a of the frame 130.

The second sheet area 126 b can be naturally spaced apart from the frame130 due to the physical properties or elasticity of the reflection sheet126 itself. That is, when the sheet area 126 b is coupled to the frame130, it naturally forms a curved surface by its self-weight and can bespaced apart from the frame 130. An isolated space 130 d can be formedbetween the second sheet area 126 b and the frame 130. In the secondsheet area 126 b, an angle formed by the reflection sheet 126 and thebottom area of the frame 130 can be gradually increased. That is, thereflection sheet 126 can be located in a two-dimensional curved lineform within the non-contact area. The same is true if the second sheetarea 126 b is spaced apart from the frame 130 at a specific angle.

The third sheet area 126 c can be seated in the third frame area 130 c.The third sheet area 126 c can be coupled to the third frame area 130 c.Alternatively, the third sheet area 126 c can be naturally laid on thethird frame area 130 c. That is, the third sheet area 126 c may comeinto contact with the third frame area 130 c due to an elastic force inthe Z direction attributable to the second sheet area 126 c forming acurved surface.

In addition, light L can be emanated through the lens 300. That is,light generated by the light source can be externally emanated throughthe lens 300. The light L emanated through the lens 300 may have variouspaths. For example, some of the light L may form a path in the sidedirection of the lens 300.

Some of the light L in the side direction path can be directed towardthe second sheet area 126 b. At least some of light generated by thelight source can be subjected to total reflection within the lens 300and directed toward the second sheet area 126 b. In such a case, light Ldirected toward the upper unit area of the second sheet area 126 b canbe greater than light L directed toward the lower area thereof. In otherwords, the amount and/or density of light L transferred to thereflection sheet 126 may not be uniform. If the amount and/or density oflight L is irregular, a user who watches the display device 100 maynotice such a difference. For example, if more light L is incident onthe upper unit area of the second sheet area 126 b than on the lowerarea, a corresponding area may look brighter than other areas due tolight L reflected by the upper unit area.

As shown in FIG. 27, an angle between two straight lines parallel to anextension line from the boundary of the first sheet area 126 a and thesecond sheet area 126 b to the boundary of the second sheet area 126 band the third sheet area 126 c and the X direction can be said to be A.The tilted angle of the second sheet area 126 b can be increased with P,that is, an intersection point between the second sheet area 126 b andthe straight line of the angle A, as its starting point. That is, theangle between the second sheet area 126 b and the X direction maysharply increase after the second sheet area 126 b passes through theintersection point P.

Since the angle of the second sheet area 126 b increases after thesecond sheet area 126 b passes through the intersection point P, densityof light L emanated from the lens (124 b of FIG. 11) per unit area canbe further increased. Accordingly, a corresponding portion may lookbrighter than other portions. Thus, a user may feel that light isirregular. In the display device 100 according to an embodiment of thepresent invention, the reflection sheet 126 can uniformly reflect light.Accordingly, a user does not feel or feels less the irregularity oflight.

As shown in FIG. 28, a dot area DT can be located in at least some areaof the reflection sheet 126 according to an embodiment of the presentinvention. A dot can be an area to which a pattern different from thatof another area has been added. The dot can be an uneven portion (orconcave-convex) portion) area formed on the reflection sheet 126.

The dot can be an area in which at least some area on the reflectionsheet 126 has been colored. For example, the dot can be an area havingrelatively dark color such as a black or gray area. The dot can be anarea in which an uneven portion and coloring have been mixed. The dotcan also have a geometric shape in which at least one of a shape, asize, a location, and color is different. For example, the dot can beany one of various shapes, such as a circle, an ellipse, a quadrangle, apole form, and a triangle formed on the reflection sheet 126, and/or acombination of various shapes.

The dot has an influence on reflectance of a corresponding area. Thatis, the dot changes reflectance of light. For example, the dot reducesreflectance of light depending on at least one of its size, shape,location, and color. A plurality of dots can be configured in the formof the dot area DT.

The dot area DT can be a set of dots. That is, the dot area DT can be aspecific area in which a plurality of dots having at least one of itsshape, size, location, and color different or identical has been formed.For example, the dot area DT can be formed in at least some area of thesecond sheet area 126 b. As described above, the second sheet area 126 bcan have high density of light per unit area in terms of its inclinedform. The dot area DT can change reflectance of light incident on thesecond sheet area 126 b. In other words, the dot area DT can increasedensity of incident light per unit area, but may decrease density ofreflected light per unit area.

Accordingly, a phenomenon in which light and darkness in a portioncorresponding to the second sheet area 126 b is different from that inother portions can be prevented. That is, light can be regularlyreflected by the entire reflection sheet 126 due to the presence of thedot area DT.

The dot area DT may include a first dot area DT1 and a second dot areaDT2. The first dot area DT1 can be a dot area DT located on thelong-side side of the reflection sheet 126. In other words, the firstdot area DT1 can be a dot area DT located between the optical assembly124 and the long side of the reflection sheet 126. The first dot areaDT1 can be located in the second sheet area 126 b. That is, the opticalassembly 124 can be located inside the horizontal bending line HBL andthe first dot area DT1 can be located outside the horizontal bendingline HBL.

The first dot area DT1 can be located in a portion corresponding to thelens. That is, at least one first dot area DT1 can be spaced apart fromanother adjacent first dot area DT1 at a specific interval. The firstdot area DT1 may have a semicircle. Accordingly, the width of the firstdot area DT1 in the first direction can be reduced toward the edge ofthe reflection sheet 126.

The second dot area DT2 can be a dot area DT located on the short-sideside of the reflection sheet 126. The second dot area DT2 can be locatedin the second sheet area 126 b. That is, the optical assembly 124 can belocated inside the vertical bending line VBL and the second dot area DT2can be located outside the vertical bending line VBL.

At least one of the attributes of the size, density, and color of dotsin the first and the second dot areas DT1 and DT2 can be graduallychanged. For example, the size of the dots in the first and the seconddot areas DT1 and DT2 may gradually increase toward the edge of thereflection sheet 126. Accordingly, light reflected by the reflectionsheet 126 can become regular.

As shown in FIG. 29, a strip area ST can be located in at least somearea of the reflection sheet 126 according to an embodiment of thepresent invention. The strip area ST may have a line form. The striparea ST can be formed to have a specific width or height or more. Thestrip area ST can be continuously formed. The strip area ST can be a setof continuous lines. A set of lines forming the strip area ST can bedifferent from another set of lines forming the strip area ST. Forexample, at least one of the thickness, length, color, and distance of aline can be different.

The strip area ST may include a first strip area ST1 and a second striparea ST2. The first and the second strip areas ST1 and ST2 can belocated in the same portions as the first and the second dot area (DT1and DT2 of FIG. 28). For example, the first strip area ST1 can belocated between the optical assembly 124 and the long side of thereflection sheet 126, and the second strip area ST2 can be locatedbetween the optical assembly 124 and the short side of the reflectionsheet 126.

The first strip area ST1 can be located in a portion corresponding tothe optical assembly 124. The first strip area ST1 may have asemicircle. Accordingly, the width of the first strip area ST1 in thefirst direction may decrease toward the edge of the reflection sheet126. The strip area ST can be located in the reflection sheet 126according to an embodiment of the present invention instead of the dotarea DT. Accordingly, overall luminance of the backlight unit can becomeuniform because reflectance of the second sheet area 126 b is furtherreduced.

As shown in FIG. 30, both the strip area ST and the dot area DT can belocated in the reflection sheet 126. The strip area ST can be locatedadjacent to the edge of the reflection sheet 126. That is, the striparea ST can be disposed farther from the optical assembly 124 than fromthe dot area DT. The dot area DT can be located between the opticalassembly 124 and the strip area ST.

Reflectance of light incident on the light source can be different inthe dot area DT and the strip area ST. For example, reflectance in thedot area DT can be greater than reflectance in the strip area ST. Inother words, reflectance in the strip area ST can be smaller thanreflectance in the dot area DT. As described above, an area close to theedge of the reflection sheet 126 can be located close to a right angleto the first sheet area 126 a due to the shape of the reflection sheet126.

Accordingly, more light can be incident on a corresponding area thanother portions. The strip area ST formed in the corresponding area canreduce reflectance of the corresponding area, thereby being capable ofmaking uniform overall luminance. As shown in FIG. 31, the dot area DTcan be located in the entire portion of the second sheet area 126 b.That is, dots can be distributed in the entire part of the second sheetarea 126 b.

As described above, at least one of the size, shape, location, and colorof the dots can be changed depending on the amount and/or density oflight that reaches the dots. For example, the size of the dots maygradually increase toward the edge portion of the second sheet area 126b, but the present invention is not limited thereto. The dot can bechanged in various manners.

In this instance, the dot area DT can be located in another portion inaddition to a portion corresponding to the optical assembly 124.Accordingly, the amount and/or density of light incident on anotherportion other than a portion corresponding to the optical assembly 124can also be controlled. Accordingly, light reflected by the reflectionsheet 126 can become further uniform.

As shown in FIG. 32, the second dot area DT2 can be spaced apart fromthe horizontal bending line HBL. A portion that belongs to the seconddot area DT2 and that corresponds to the optical assembly 124 can bemore protruded toward the optical assembly 124 than another portion. Aportion that belongs to the second dot area DT2 and that corresponds tothe optical assembly can be spaced apart from the horizontal bendingline HBL at a first dot interval HD1, and another portion can be spacedapart from the horizontal bending line HBL at a second dot interval HD2.The first dot interval HD1 can be shorter than the second dot intervalHD2.

At least one of the attributes of the size, density, and color of theprotruding unit that belongs to the second dot area DT2 and thatcorresponds to the optical assembly 124 can be different from that ofanother portion. For example, the size of a dot in the protruding unitthat belongs to the second dot area DT2 and that corresponds to theoptical assembly 124 can be greater than that in another portion.Accordingly, light reflected by the reflection sheet 126 can becomeuniform.

In the following description, a display panel 420′ may include a firstlong side LS1′, a second long side LS2′ facing the first long side LS1′,a first short side SS1′ neighboring the first long side LS1′ and thesecond long side LS2′, and a second short side SS2′ facing the firstshort side SS1′.

In this instance, the first short side SS1′ can be said to be a firstside area, and the second short side SS2′ can be said to be a secondside area facing the first side area. The first long side LS1′ can besaid to be a third side area neighboring the first side area and thesecond side area and located between the first side area and the secondside area. In addition, the second long side LS2′ can be said to be afourth side area neighboring the first side area and the second sidearea, located between the first side area and the second side area, andfacing the third side area.

Furthermore, the first or second long side LS1′ or LS2′ has beenillustrated as having a longer length than the first or second shortside SS1′ or SS2′, for convenience of description, but the first orsecond long side LS1′ or LS2′ may have almost the same length as thefirst or second short side SS1′ or SS2′.

In the following description, a first direction DR1 can be a directionparallel to the long sides LS1′ and LS2′ of a display panel 110′, and asecond direction DR2 can be a direction parallel to the short sides SS1′and SS2′ of the display panel 110′. A third direction DR3 can be adirection perpendicular to the first direction DR1 and/or the seconddirection DR2. The first direction DR1 and the second direction DR2 canbe collectively called a horizontal direction. Furthermore, the thirddirection DR3 can be called a vertical direction.

Next, FIGS. 33 and 34 are diagrams showing a display device according toan embodiment of the present invention. As shown in FIGS. 33 and 34, thedisplay device 100′ according to an embodiment of the present inventionincludes a display panel 110′ and a back cover 150′ at the back of thedisplay panel 110′.

The back cover 150′ can be connected to the display panel 110′ in asliding manner in the direction from the first long side LS1′ to thesecond long side LS2′, that is, a second direction DR2. In other words,the back cover 150′ can be inserted in a sliding manner from the firstshort side SS1′ of the display panel 110′, the second short side SS2′facing the first short side SS1′, and the first long side LS1′neighboring the first and the second short sides SS1′ and SS2′ andlocated between the first short side SS1′ and the second short sideSS2′. In order to connect the back cover 150′ to the display panel 110′in a sliding manner, a protruding unit, a sliding unit, a coupling part,etc. can be included in the back cover 150′ and/or another structureadjacent to the back cover 150′.

FIGS. 35 to 39 are diagrams showing the configuration of a displaydevice related to an embodiment of the present invention. As shown inFIG. 35, the display device 100′ according to an embodiment of thepresent invention includes a front cover 105′, a display panel 110′, abacklight unit 120′, a frame 130′, and a back cover 150′.

The front cover 105′ covers at least some area of the front and side ofthe display panel 110′, and the front cover 105′ has a rectangular frameshape having an empty center. Since the center of the front cover 105′is empty, an image of the display panel 110′ can be displayed to theoutside.

The front cover 105′ can be divided into a front cover and a side cover.That is, the front cover 105′ can be divided into the front cover placedon the front side of the display panel 110′ and the side cover placed onthe side of the display panel 110′. The front cover and the side covercan be separately configured. Any one of the front cover and the sidecover can be omitted. For example, the front cover is not present andonly the side cover is present for the purpose of an aesthetic design,etc.

The display panel 110′ is provided at the front of the display device100′, and an image is displayed on the display panel 110′. The displaypanel 110′ can divide an image into a plurality of pixels and output theimage according to color, brightness, and chroma for each pixel. Thedisplay panel 110′ can be divided into an active area in which an imageis displayed and an inactive area in which an image is not displayed.The display panel 110′ also includes a front substrate and a rearsubstrate facing each other with a liquid crystal layer interposedtherebetween.

The front substrate may include a plurality of pixels including red (R),green (G), and blue (B) subpixels and can generate an imagecorresponding to red, green or blue color in response to a controlsignal. The rear substrate may include switching elements and can switcha pixel electrode. For example, the pixel electrode can change thearrangement of the molecules of the liquid crystal layer in response toan external control signal.

The liquid crystal layer includes a plurality of liquid crystalmolecules. The arrangement of the liquid crystal molecules can bechanged in accordance with a voltage difference generated between thepixel electrode and a common electrode. In addition, the liquid crystallayer can transfer light, supplied by the backlight unit 120′, to thefront substrate.

The backlight unit 120′ is located at the back of the display panel 110′and includes a plurality of light sources. The light source of thebacklight unit 120′ can be disposed in a direct type or an edge type.For an edge type backlight unit 120′, a light guide panel is furtherincluded.

In addition, the backlight unit 120′ can be coupled to the front of aframe 140′. For example, the plurality of light sources can be disposedon the front side of the frame 140′. In such a case, the backlight unit120′ can be commonly called a direct type backlight unit.

The backlight unit 120′ can be driven using a total driving method or apartial driving method, such as local dimming or impulsive. Thebacklight unit 120′ may also include an optical sheet 125′ and anoptical layer 123′. The optical sheet 125′ enables light of the lightsource to be uniformly delivered to the display panel 110′. The opticalsheet 125′ may include a plurality of layers. For example, the opticalsheet 125′ may include at least one prism sheet and/or at least onediffusion sheet.

The optical sheet 125′ may include at least one coupling part 125 d′.The coupling part 125 d′ can be coupled to the front cover 105′ and/orthe back cover 150′. That is, the coupling part 125 d′ can be directlycoupled to the front cover 105′ and/or the back cover 150′.Alternatively, the coupling part 125 d′ can be coupled to a structurecoupled to the front cover 105′ and/or the back cover 150′. That is, thecoupling part 125 d′ can be indirectly coupled to the front cover 105′and/or the back cover 150′.

The optical layer 123′ may include the light source and so on. Theoptical layer 123′ is described in detail in a corresponding part. Theframe 130′ functions to support elements of the display device 100′. Forexample, an element, such as the backlight unit 120′, can be coupled tothe frame 130′. The frame 130′ can be made of a metallic material, suchas an aluminum alloy.

The back cover 150′ can be located at the backside of the display device100′ and protects internal elements from the outside. At least some ofthe back cover 150′ can be coupled to the frame 130′ and/or the frontcover 105′. The back cover 150′ can be an injected matter made of resin.

Next, FIG. 36 is a diagram showing elements, such as the optical sheet125′. As shown in FIG. 36(a), the optical sheet 125′ can be locatedabove the frame 130′. The optical sheet 125′ can be coupled to the frame130′ at the edge of the frame 130′.

The optical sheet 125′ can be directly seated in the edge of the frame130′. That is, the outer circumference of the optical sheet 125′ can besupported by the frame 130′. The upper surface of the edge of theoptical sheet 125′ can be surrounded by a first guide panel 117′. Forexample, the optical sheet 125′ can be located between the edge of theframe 130′ and the flange 117′a of the first guide panel 117′.

The display panel 110′ can be located on the front side of the opticalsheet 125′. The edge of the display panel 110′ can be coupled to thefirst guide panel 117′. That is, the display panel 110′ can be supportedby the first guide panel 117′. The edge area of the front of the displaypanel 110′ can be surrounded by the front cover 105′. For example, thedisplay panel 110′ can be located between the first guide panel 117′ andthe front cover 105′.

As shown in FIG. 36(b), the display device 100′ according to anembodiment of the present invention may further include a second guidepanel 113′. The optical sheet 125′ can be coupled to the second guidepanel 113′. That is, the second guide panel 113′ can be coupled to theframe 130′ and the optical sheet 125′ can be coupled to the second guidepanel 113′. The second guide panel 113′ can be made of a materialdifferent from that of the frame 130′. The frame 130′ may have a formthat surrounds the first and the second guide panels 117′ and 113′.

As shown in FIG. 36(c), in the display device 100′ according to anembodiment of the present invention, the front cover 105′ may not coverthe front of the display panel 110′. That is, one end of the front cover105′ can be located on the side of the display panel 110′.

Referring to FIGS. 37 and 38, the backlight unit 120′ may include asubstrate 122′, at least one optical assembly 124′, the optical layer123′ including a reflection sheet 126′ and a diffusion plate 129′, andthe optical sheet 125′ located on the front side of the optical layer123′. The substrate 122′ may have a plurality of strip forms extended inthe first direction and spaced apart from each other at a specificinterval in the second direction orthogonal to the first direction.

At least one optical assembly 124′ can be mounted on the substrate 122′.An electrode pattern for connecting an adapter and the optical assembly124′ can be formed on the substrate 122′. For example, a carbon nanotubepattern for connecting the optical assembly 124′ and the adapter can beformed on the substrate 122′.

The substrate 122′ can be made of at least one of polyethyleneterephthalate (PET), glass, polycarbonate (PC), and silicon. Thesubstrate 122′ can be a printed circuit board (PCB) on which at leastone optical assembly 124′ is mounted.

The optical assembly 124′ can be disposed on the substrate 122′ at aspecific interval in the first direction. The diameter of the opticalassembly 124′ can be greater than the width of the substrate 122′. Thatis, the diameter of the optical assembly 124′ can be greater than thelength of the substrate 122′ in the second direction.

The optical assembly 124′ can be a light-emitting diode (LED) chip or alight-emitting diode package including at least one LED chip. Theoptical assembly 124′ may include a colored LED that emits at least oneof red, blue, and green or a white LED. The colored LED may include atleast one of a red LED, a blue LED, and a green LED.

The light source included in the optical assembly 124′ can be a chip onboard (COB) type. The COB type may have a form in which an LED chip,that is, a light source, has been directly coupled to the substrate122′. Accordingly, the process can be simplified. Furthermore,resistance can be lowered, thereby being capable of reducing energy lostdue to heat. That is, power efficiency of the optical assembly 124′ canbe improved. The COB type can provide brighter lighting. The COB typecan be implemented thin and light compared to a related art technology.

The reflection sheet 126′ can be located on the front side of thesubstrate 122′. The reflection sheet 126′ can be located on an areaother than the area in which the optical assembly 124′ of the substrate122′ has been formed. That is, a plurality of through holes 235′ can beformed in the reflection sheet 126′.

The reflection sheet 126′ reflects light, emitted from the opticalassembly 124′, toward the front side. Furthermore, the reflection sheet126′ can reflect light, reflected by the diffusion plate 129′, again.The reflection sheet 126′ includes at least one of metal and metaloxide, that is, reflection materials. For example, the reflection sheet126′ may include metal and/or metal oxide having high reflectance, suchas at least one of aluminum (Al), silver (Ag), gold (Au), and titaniumdioxide (TiO2).

The reflection sheet 126′ can be formed by depositing and/or coatingmetal or metal oxide on the substrate 122′. Ink including a metallicmaterial can be printed on the reflection sheet 126′. A deposition layerusing a vacuum deposition method, such as a thermal deposition method,an evaporation method or a sputtering method, can be formed in thereflection sheet 126′. A coating layer and/or a print layer using aprinting method, a gravure coating method or a silk screen method can beformed in the reflection sheet 126′.

An air gap can be located between the reflection sheet 126′ and thediffusion plate 129′. The air gap can function as a buffer capable ofwidely spreading light emitted from the optical assembly 124′. Resin canbe deposited on the optical assembly 124′ and/or the reflection sheet126′. The resin can function to spread light emitted from the opticalassembly 124′.

The diffusion plate 129′ spreads light emitted from the optical assembly124′ to the upper part. The optical sheet 125′ can be located on thefront side of the diffusion plate 129′. The backside of the opticalsheet 125′ may closely adhere to the diffusion plate 129′, and the frontsurface of the optical sheet 125′ may closely adhere to the backside ofthe display panel 110′.

The optical sheet 125′ may include at least one sheet such as one ormore prism sheets and/or one or more diffusion sheets. The plurality ofsheets included in the optical sheet 125′ can be in an adhesion and/orclose adhesion state.

The optical sheet 125′ may include a plurality of sheets havingdifferent functions. For example, the optical sheet 125′ can includefirst to third optical sheets 125 a′ to 125 c′. The first optical sheet125 a′ can have a function of a diffusion sheet, and the second and thethird optical sheets 125 b′ and 125 c′ can have a function of a prismsheet. The number and/or location of the diffusion sheet and the prismsheet can be changed. For example, the optical sheet 125′ may includethe first optical sheet 125 a′, that is, a diffusion sheet, and thesecond optical sheet 125 b′, that is, a prism sheet.

The diffusion sheet can make luminance of light more uniformly bypreventing light emitted from the diffusion plate from being partiallyconcentrated. The prism sheet can condense light emitted from thediffusion sheet so that the light is vertically incident on the displaypanel 110′. The coupling part 125 d′ can be formed in at least one ofthe edges of the optical sheet 125′. The coupling part 125 d′ can beformed in at least one of the first to the third optical sheets 125 a′to 125 c′.

The coupling part 125 d′ can be formed in an edge on the long-side sideof the optical sheet 125′. The coupling part 125 d′ formed on the firstlong-side side and the coupling part 125 d′ formed on the secondlong-side side can be asymmetric. For example, the location and/ornumber of coupling parts 125 d′ on the first long-side side and thelocation and/or number of coupling parts 125 d′ on the second long-sideside can be different.

Referring to FIG. 39, the substrate 122′, including a plurality ofstrips extended in the first direction and spaced apart from each otherat a specific interval in the second direction orthogonal to the firstdirection, can be provided on the frame 130′. Ends on one side of theplurality of substrates 122′ can be connected to a wiring electrode232′.

The wiring electrode 232′ can be extended in the second direction. Thewiring electrode 232′ can be connected to the ends on one side of thesubstrates 122′ at a specific interval in the second direction. Thesubstrate 122′ can be electrically connected to an adapter through thewiring electrode 232′.

The optical assemblies 124′ can be mounted on the substrate 122′ at aspecific interval in the first direction. The diameter of the opticalassembly 124′ can be greater than the width of the substrate 122′ in thesecond direction. Accordingly, the outside area of the optical assembly124′ can be over an area in which the substrate 122′ is not provided.

FIGS. 40 and 41 are diagrams showing a light source according to anembodiment of the present invention. As shown in FIG. 40, the lightsource 203′ can be a COB type. The light source 203′ of a COB type mayinclude at least one of a light emission layer 135′, first and secondelectrodes 147′ and 149′, and a fluorescent layer 137′.

The light emission layer 135′ can be located the substrate 122′ and canemit light of any one of blue, red, and green. The light emission layer135′ may include any one of Firpic, (CF3ppy)2Ir(pic), 9, 10-di2-naphthyl)anthracene(AND), Perylene, distyrybiphenyl, PVK, OXD-7, andUGH-3(Blue) and a combination of them.

The first and the second electrodes 147′ and 149′ can be located on bothsides of the bottom of the light emission layer 135′. The first and thesecond electrodes 147′ and 149′ can transfer an external driving signalto the light emission layer 135′. The fluorescent layer 137′ can coverthe light emission layer 135′ and the first and the second electrodes147′ and 149′. The fluorescent layer 137′ includes a fluorescentmaterial that converts light of a spectrum, generated by the lightemission layer 135′, in white light. The light emission layer 135′ mayhave a uniform thickness on the fluorescent layer 137′. The fluorescentlayer 137′ may have a refractive index of 1.4 to 2.0.

The light source 203′ of a COB type according to an embodiment of thepresent invention can be directly mounted on the substrate 122′.Accordingly, the size of the optical assembly 124′ can be reduced. Thelight source 203′ can be driven with a high current due to excellentradiation because it is located on the substrate 122′. Accordingly, thenumber of light sources 203′ used to secure the same amount of light canbe reduced. A wire bonding process is not required because the lightsource 203′ is mounted on the substrate 122′. Accordingly, a cost can bereduced because the process is simplified.

As shown in FIG. 41, the emission of the light source 203′ according toan embodiment of the present invention can be performed in a first lightemission area EA1′. That is, light emission can be performed in an areaincluding a second light emission area EA2′, that is, the front side,and third and fourth light emission areas EA3′ and EA4′, that is, thesides. Such a point is different from a point that a related art lightsource including the POB type emits light in the second light emissionarea EA2′. That is, the light source 203′ according to an embodiment ofthe present invention can emit light in a wide range including the sidesof the light source 203′.

FIG. 42 is a diagram showing an optical assembly including the lightsources of FIG. 41. As shown in FIG. 42, according to an embodiment ofthe present invention, a plurality of the optical assemblies 124′ can bespaced apart from each other and disposed along the substrate 122′. Theoptical assembly 124′ includes a light source 203′ and a lens 300′located on one side of the light source 203′.

The light source 203′ may include various sources that emit light. Forexample, the light source 203′ can be an LED of a COB type, such as thatdescribed above. The lens 300′ can be located on the light source 203′.At least some area of the light source 203′ overlaps the lens 300′. Forexample, the light source 203′ can be inserted into a groove within thelens 300′. Alternatively, an area that belongs to the light source 203′and from which light is substantially emitted can be inserted into thelower part of the lens 300′. For example, if a leg structure is presentin the lens 300′, part of the upper side of the light source 203′ can beinserted into the lower side of the lens 300′.

The lens 300′ may have a form in which some of light emitted from thelight source 203′ is reflected and some of the light is refracted. Forexample, the lens 300′ can be a reflection/refraction type lens or areflection type lens. Light from the light source 203′ can be uniformlyspread in all directions by reflection in some areas of the lens 300′and/or refraction in some areas of the lens 300′.

The light source 203′ inserted into the lens 300′ can be closely adheredto the lens 300′. For example, the lens 300′ and the light source 203′can be bonded together by adhesives. Each lens 300′ may correspond toeach light source 203′. For example, first to third lenses 300 a′ to 300c′ can be located over first to third light sources 203 a′ to 203 c′,respectively.

The lens 300′ controls the path of light emitted from the light source203′. That is, the lens 300′ can prevent light from the light source203′ from being concentrated on a specific point. In other words, thelens 300′ can uniformly diffuse light from the light source 203′. Thelens 300′ according to an embodiment of the present invention caneffectively control the path of light from the light source 230′ andeffectively control side light of the light source 203′.

FIG. 43 is a perspective view of a lens according to an embodiment ofthe present invention. The lens 300′ according to an embodiment of thepresent invention includes a first surface 310′, a second surface 320′,a third surface 330′, and a lens extension part 340′. The lens 300′generally has a cylinder or truncated cone shape. The lens 300′according to an embodiment of the present invention, together with thelight source 203′, forms the optical assembly 124′. The lens 300′ canform the backlight unit 120′ along with the frame 130′, the substrate122′, the reflection sheet 125′, and the light source 203′. In addition,the lens 300′ can form the display device 100′ along with the frame130′, the substrate 122′, the reflection sheet 125′, the light source203′, and the display panel 110′.

The first surface 310′ has a circular section shape. The first surface310′ forms the upper part of the lens 300′. The upper part of the lens300′ can be located in a negative Z-axis direction, as shown in FIG. 43.In FIG. 43, the XYZ coordinate system is the Cartesian coordinates andcan be set in the left-handed direction. The first surface 310′ can besubstantially the same as or can be parallel to an XY plane.

The second surface 320′ can be opposite the first surface 310′ and canform the lower part of the lens 300′. The second surface 320′ may have acircular section shape. The lower part of the lens 300′ can be locatedin a positive Z-axis direction, as shown in FIG. 43. At least some ofthe second surface 320′ forms a bottom BS′ parallel to the first surface310′. The bottom BS′ can be substantially the same as or can be parallelto the XY plane.

A mounting part 323′ connected to the substrate 122′ can be formed inthe second surface 320′ and have a protrusion shape. The mounting part323′ can be directed toward the positive Z axis. A concave part 325′facing the light source 203′ and having a shape convex with respect tothe first surface 310′ can be formed in the second surface 320′.

The third surface 330′ may connect the first surface 310′ and the secondsurface 320′. The third surface 330′ can also be unfolded. That is, thethird surface 330′ can be unfolded on a plane using a segment,connecting one point coming into contact with the first surface 310′ andone point coming into contact with the second surface 320′, as acutting-plane line.

The lens extension part 340′ can be formed in some area of the thirdsurface 330′. In addition, the lens extension part 340′ extends towardthe outer side in the radius direction of the second surface 320′. Thelens extension part 340′ and the third surface 330′ can be formed to beintegrated. Further, the lens extension part 340′ can be formed as asegment in the direction parallel to the outer circumference of thesecond surface 320′ and can closely attach the reflection sheet 125′ tothe frame 130′. When the lens extension part 340′ is formed as asegment, the lens extension part 340′ can be formed in accordance withthe height of the reflection sheet 125′ although the height of thereflection sheet 125′ is changed in the direction parallel to the outercircumference. Accordingly, the lens extension part 340′ can efficientlyattach the reflection sheet 125′ to the frame 130′.

Alternatively, a plurality of the lens extension parts 340′ can beconnected to one in the direction parallel to the outer circumference ofthe second surface 320′, and thus have substantially the same shape asan annular shape. If the lens extension parts 340′ are connected to onein the direction parallel to the outer circumference of the secondsurface 320′, the lens extension part 340′ can be isomorphic with adoughnut. From a standpoint of topology, the lens extension part 340′according to an embodiment of the present invention is isomorphic with asphere. Thus, a plurality of the lens extension parts 340′ can beprovided.

The boundary of the lens extension part 340′ and the third surface 330′can be virtually formed. The lens extension part 340′ can effectivelyprevent the reflection sheet 126′ from being lifted off. The number ofpins that closely attach the reflection sheet 126′ to the frame 130′ canbe reduced and overall process efficiency can be improved because thelens extension part 340′ prevents the reflection sheet 126′ from beinglifted off from the frame 130′.

FIG. 44 is a diagram showing a cross section of FIG. 43 taken along lineA-O-A′. As shown in FIG. 44, the bottom BS′ can be substantiallyparallel to the first surface 310′. As shown in FIG. 44, the mountingpart 323′ can be formed in the second surface 320′. The mounting part323′ and the bottom BS′ can be integrated and thus the mounting part323′, together with the bottom BS′, may have a virtual boundary.

As shown in FIG. 44, the lens extension part 340′ can be extended fromthe third surface 330′. The lens extension part 340′, together with thethird surface 330′ forms a virtual boundary surface. In this instance,the virtual boundary surface of the third surface 330′ and the lensextension part 340′ is not an actually formed boundary surface, but canbe present in a virtual or ideational viewpoint. A ray of light thatpasses through the concave part 325′ and travels to the inside of thelens 300′ may describe the boundary surface of the third surface 330′and the lens extension part 340′.

It can be assumed that a ray of light passing through the concave part325′ and traveling to the inside of the lens 300′ has reached theboundary surface of the third surface 330′ and the lens extension part340′. If a boundary surface is actually present between the thirdsurface 330′ and the lens extension part 340′, the path of a ray oflight passing through the boundary surface can be bent at the boundarysurface. In an embodiment of the present invention, however, the path ofa ray of light passing through the boundary surface may not be bent atthe boundary surface of the lens extension part 340′ and the thirdsurface 330′ because the boundary surface is a virtual boundary surface.

FIG. 45 is a diagram showing a cross section of FIG. 43 taken along lineB-O-B′. As shown in FIG. 45, the lens 300′ includes the first surface310′, the second surface 320′, and the third surface 330′. The firstsurface 310′ forms the upper part of the lens 300′, and the secondsurface 320′ forms the lower part of the lens 300′. The second surface320′ also includes the bottom BS′ substantially parallel to the firstsurface 310′ and the concave part 325′. The third surface 330′ alsoconnects the first surface 310′ and the second surface 320′.

FIG. 46 is a diagram showing the lens in which the lens extension parthas been disposed in accordance with an embodiment of the presentinvention. In FIG. 46, the mounting part, the concave part, etc. areomitted. In FIG. 46, a virtual line VL′ is a virtual line located on thethird surface 330′ and is not a line actually indicated on the thirdsurface 330′. The virtual line VL′ is introduced to easily describe thedeployment of the lens extension part 340′.

The virtual line VL′ can maintain a specific interval at the boundary ofthe second surface 320′ and the third surface 330′. That is, the virtualline VL′ can be spaced apart from the bottom BS′ at a specific interval.In other words, the virtual line VL′ can be located on a single plane.The plane including the virtual line VL′ can be substantially parallelto the bottom BS′. The virtual line VL′ may include a first virtual linepiece VL1′ and a second virtual line piece VL2′. The virtual line VL′according to an embodiment of the present invention has a configurationin which the first virtual line piece VL1′ and the second virtual linepiece VL2′ are alternately disposed.

The first virtual line piece VL1′ can be covered with the lens extensionpart 340′. If the lens extension part 340′ has constant height from thebottom BS′ or has an annular shape extended from the bottom BS′, thevirtual line VL′ can be formed of a single first virtual line pieceVL1′. The first virtual line piece VL1′ can be located on the virtualboundary surface of the third surface 330′ and the lens extension part340′. Both ends of the first virtual line piece VL1′ can be connected tothe second virtual line pieces VL2′, respectively. In FIG. 46, the firstvirtual line piece VL1′ has been indicated by a chain-dashed line andhas been indicated by a double line for convenience.

The second virtual line piece VL2′ can be externally exposed. If thelens extension part 340′ is not included in the lens 300′, a specificvirtual line VL′ may include a single second virtual line piece VL2′.Both ends of the second virtual line piece VL2′ can be connected to thefirst virtual line pieces VL1′, respectively. That is, the secondvirtual line piece VL2′ and the first virtual line piece VL1′ can bealternately disposed. In FIG. 46, the second virtual line piece VL2′ hasbeen indicated by a two-dot chain line.

FIG. 47 is an unfolded view of the third surface of FIG. 46. In FIG. 47,the leftmost second virtual line piece VL2′ and the rightmost secondvirtual line piece VL2′ can be the same and can be cut for unfolding.The virtual line VL′ is placed on the third surface 330′, and mayinclude the first virtual line piece VL1′ and the second virtual linepiece VL2′. A single virtual line VL′ can be formed as shown in FIG. 47.Alternatively, a plurality of the virtual lines VL′ can be formed. Forexample, if a plurality of the lens extension parts 340′ is formed andhas different height from the bottom BS′, a plurality of differentvirtual lines VL′ can be formed.

As shown in FIG. 47, the first virtual line piece VL1′ and the secondvirtual line piece VL2′ can be alternately disposed. That is, the firstvirtual line piece VL1′ and the second virtual line piece VL2′ can bealternately disposed on the third surface 330′. Since the first virtualline piece VL1′ is covered with the lens extension part 340′, the lensextension part 340′ can be located at the place where the first virtualline piece VL1′ is located.

FIG. 48 is a diagram showing the substrate in which the optical assemblyis disposed in accordance with an embodiment of the present invention.In particular, FIG. 48 is a diagram seen from the top of the opticalassembly 124′. That is, the first surface 310′ of the lens 300′ is shownin FIG. 48.

The substrate 122′ includes a first long side LE1′, a second long sideLE2′, a first short side SE1′, and a second short side SE2′. The firstlong side LE1′ and the second long side LE2′ are parallel to each otherand can be the length direction of the substrate 122′. The first shortside SE1′ and the second short side SE2′ connects the first long sideLE1′ and the second long side LE2′. The first long side LE1′, the firstshort side SE1′, the second long side LE2′, and the second short sideSE2′ are sequentially connected, and form a quadrangle or rectangle.

The optical assembly 124′ includes the lens 300′ and the light source203′. In FIG. 48, the light source 203′ is not shown. The opticalassembly 124′ can be disposed on the substrate 122′ in a directionparallel to the first long side LE1′. That is, the optical assembly 124′can be disposed on the substrate 122′ in a direction parallel to thesecond long side LE2′. In other words, the optical assembly 124′ can bedisposed on the substrate 122′ in the length direction of the substrate122′. In FIG. 48, the length direction of the substrate 122′ is theX-axis direction.

The lens 300′ included in the optical assembly 124′ includes the lensextension part 340′. As shown in FIG. 48, the diameter of the lens 300′can be greater than the width of the substrate 122′. In other words, atleast one of the diameter of the first surface 310′ of the lens 300′ andthe diameter of the second surface 320′ can be greater than the width ofthe substrate 122′.

FIG. 49 is a diagram showing the deployment of the reflection sheet andthe substrate according to an embodiment of the present invention. Thereflection sheet 126′ covers part of the substrate 122′. The lightsource 203′ can be disposed in an area that belongs to the substrate122′ and that is not covered with the reflection sheet 126′.Furthermore, a substrate groove SD′ can be located in an area thatbelongs to the substrate 122′ and that is not covered with thereflection sheet 126′. The substrate 122′ covered with the reflectionsheet 126′ is indicated by a dotted line in FIG. 49. In FIG. 49, thelength direction of the substrate 122′ can be the X axis.

The light source 203′ can be connected to the substrate 122′ andsupplied with power to generate light. The substrate groove SD′ can beformed in the substrate 122′ and be connected to the mounting part 323′of the lens 300′. The substrate groove SD′ can be disposed in thesubstrate 122′ in accordance with the location of the mounting part323′. Since the substrate groove SD′ is formed, the lens 300′ can beeasily mounted on the substrate 122′.

The reflection sheet 126′ covers the substrate 122′ other than an areaon which the lens 300′ will be mounted. An area that belongs to the areaof the reflection sheet 126′ and that corresponds to a shape of the lens300′ mounted on the substrate 122′ may not include the reflection sheet126′. In other words, an area that belongs to the area of the reflectionsheet 126′ and that corresponds to a shape of the lens 300′ mounted onthe substrate 122′ may not be included in the entire area of thereflection sheet 126′.

An indication groove IXD′ can be formed in addition to the area thatbelongs to the area of the reflection sheet 126′ and that corresponds toa shape of the lens 300′ mounted on the substrate 122′. The indicationgroove IXD′ can be formed to abut on the area that belongs to the areaof the reflection sheet 126′ and that corresponds to a shape of the lens300′ mounted on the substrate 122′. The indication groove IXD′ mayindicate the direction in which the lens 300′ is mounted when the lens300′ is mounted on the substrate 122′.

FIG. 50 is a diagram showing the state in which the lens has beenmounted on the substrate of FIG. 49. In FIG. 50, the first long sideLE1′ is the X-axis direction. In FIG. 50, the first surface 310′ and thethird surface 330′ have been omitted from the lens 300′. That is, FIG.50 shows the state in which the lens 300′ has been mounted on thesubstrate 122′ covered with the reflection sheet 126′. A shape of thelens 300′ mounted on the substrate 122′ can be effectively expressedusing the second surface 320′ and the lens extension part 340′.

The lens 300′ can be mounted on the substrate 122′ and include aplurality of the lens extension parts 340′. As shown in FIG. 50, one ofthe plurality of lens extension parts 340′ can be located in accordancewith the indication groove IXD′ formed in the reflection sheet 126′.Since at least one of the lens extension parts 340′ is located inaccordance with the indication groove IXD′ formed in the reflectionsheet 126′, the mounting part 323′ formed in the lens 300′ can belocated in accordance with the substrate groove SD′ formed in thesubstrate 122′. That is, the lens 300′ can be easily mounted on thesubstrate 122′ because at least one of the lens extension parts 340′ islocated in accordance with the indication groove IXD′ formed in thereflection sheet 126′.

As shown in FIG. 50, at least another of the plurality of lens extensionparts 340′ can be spaced apart from the space between the first longside LE1′ and the second long side LE2′. If the lens extension part 340′is spaced apart from the space between the first long side LE1′ and thesecond long side LE2′ as described above, the lens extension part 340′can closely attach the reflection sheet 340′ not overlapping thesubstrate 122′ to the frame 130′. In this instance, the frame 130′ canbe the frame 130′ of the display device 100′ shown in FIG. 33.

Next, FIG. 51 is a diagram showing a cross section of FIG. 50 takenalong line O-A. That is, FIG. 51 may show a cross section of FIG. 50taken from the light source 203′ to the indication groove IXD′. Forexample, FIG. 51 may show the XZ plane in FIG. 50. The light source 203′can be disposed on the substrate 122′.

As shown in FIG. 51, the reflection sheet 126′ can be located on thesubstrate 122′. In FIG. 51, the lens extension part 340′ may notinteract with the reflection sheet 126′. That is, the lens extensionpart 340′ of FIG. 51 can indicate the orientation of the lens 300′disposed on the substrate 122′. In other words, the lens extension part340′ of FIG. 51 can correspond to the indication groove IXD′ formed inthe reflection sheet 126′.

FIG. 52 is a diagram showing a cross section of FIG. 50 taken along lineO-B. That is, FIG. 52 shows a cross section of FIG. 50 taken from thelight source 203′ to one lens extension part 340′. In this instance, thelens extension part 340′ can be spaced apart from the space between thefirst long side LE1′ and the second long side LE2′.

As shown in FIG. 52, the lens extension part 340′ covers part of thereflection sheet 126′. That is, the lens extension part 340′ can applypressure in the Z-axis direction so that the reflection sheet 126′closely adheres to the frame 130′.

At least part of the reflection sheet 126′ can be located over the frame130′. That is, it is preferable to apply pressure to the reflectionsheet 126′ so that at least part of the reflection sheet 126′ closelyadheres to the frame 130′. A fixing pin can closely attach thereflection sheet 126′ to the frame 130′. According to an embodiment ofthe present invention, the lens extension part 340′ according to anembodiment of the present invention can perform the same function as thefixing pin because at least part of the reflection sheet 126′ is locatedbetween the lens extension part 340′ and the frame 130′. Processefficiency can be improved because the reflection sheet 126′ can besubstantially fixed at the same time by mounting the lens 300′ on thesubstrate 122′.

FIG. 53 is a diagram showing another embodiment in which the lens hasbeen mounted on the substrate of FIG. 49. As shown in FIG. 53, accordingto an embodiment of the present invention, six lens extension parts 340′can be provided. One of the six lens extension parts 340′ can bedisposed to correspond to the indication groove IXD′ formed in thereflection sheet 126′.

A lens extension part 340′ that overlaps the substrate 122′ other thanthe lens extension part 340′ corresponding to the indication groove IXD′can be present. That is, unlike in the embodiment of FIG. 50, in theembodiment of the present invention shown in FIG. 53, an area in whichthe substrate 122′ and the reflection sheet 126′ and the lens extensionpart 340′ overlap can be present.

FIG. 54 is a diagram showing a cross section of FIG. 53 taken along lineB-O-A. A cross section area taken along line O-A can be substantiallythe same as FIG. 51. A cross section area taken along line O-B can bedifferent from FIG. 52. That is, the lens extension part 340′ mayoverlap the reflection sheet 126′ on the substrate 122′. In other words,the lens extension part 340′ may apply pressure to the reflection sheet126′ on the substrate 122′. In this instance, the lens extension part340′ can closely attach the reflection sheet 126′ to the frame 130′.

The location of a lens extension part 340A′ on the left side of FIG. 54can be different from that of a lens extension part 340B′ on the rightside of FIG. 54. That is, the lens extension part 340A′ on the left sideof FIG. 54 can be located in a negative Z-axis direction compared to thelens extension part 340B′ on the right side of FIG. 54. In other words,the lens extension part 340A′ on the left side of FIG. 54 can be locatedon the upper part compared to the lens extension part 340B′ on the rightside of FIG. 54.

FIG. 55 is a diagram showing yet another embodiment in which the lenshas been mounted on the substrate of FIG. 49. As shown in FIG. 55,according to an embodiment of the present invention, four lens extensionparts 340′ can be provided. One of the four lens extension parts 340′can be disposed to correspond to the indication groove IXD′ formed inthe reflection sheet 126′.

The length of the lens extension part 340′ according to the outercircumference of the lens 300′ can be greater than the length of thelens extension part 340′ in a direction vertical to the outercircumference of the lens 300′. That is, the lens extension part 340′may have a blade shape in addition to a protruded shape. In other words,the degree to which the lens extension part 340′ surrounds the lens 300′can be greater than the degree to which the lens extension part 340′ isprotruded. In this instance, the reflection sheet 126′ can be closelyattached to the frame more stably. Furthermore, side light generated bythe light source can be effectively controlled.

FIG. 56 is a diagram showing a cross section of FIG. 55 taken along lineA2-O-A1. A lens extension part 340A′ on the right side of FIG. 56 can belocated on the same position as a lens extension part 340B′ on the leftside of FIG. 56 in the Z axis. That is, both the lens extension parts340A′ and 340B′ can be located at the same height.

The lens extension part 340B′ on the left side of FIG. 56 can closelyattach the reflection sheet 126′ to the frame 130′. The lens extensionpart 340A′ on the right side of FIG. 56 can be located in the indicationgroove IXD′ formed in the reflection sheet 126′, and thus may notclosely attach the reflection sheet 126′ to the frame 130′.

FIG. 57 is a diagram showing a cross section of FIG. 55 taken along lineA3-O-A2. The lens extension part 340B′ on the right of FIG. 57 can bedisposed at a lower location than a lens extension part 340C′ on theleft side of FIG. 57 in the Z axis. That is, both the lens extensionparts 340C′ and 340B′ can be located at different heights.

The lens extension part 340C′ on the left side of FIG. 57 can closelyattach the reflection sheet 126′ to the substrate 122′. That is, thelens extension part 340C′ on the left side of FIG. 57 can closely attachthe reflection sheet 126′ to the frame 130′. The lens extension part340C′ on the left side of FIG. 57 can be disposed at a higher locationthan the lens extension part 340B′ on the right side of FIG. 57 in the Zaxis because it closely attaches the reflection sheet 126′ to thesubstrate 122′. The lens extension part 340B′ on the right side of FIG.57 can closely attach the reflection sheet 126′ to the frame 130′.

The lens extension part 340C′ on the left side of FIG. 57 can bedisposed at a higher location than the bottom BS′. Accordingly, theremay be a problem in that side light generated by the light source 203′travels toward A3. If side light generated by the light source 203′travels toward A3, it may travel to the outside through the thirdsurface 330′. The externally traveled side light meets the reflectionsheet 126′ and can be reflected or scattered again.

FIG. 58 is a diagram showing the path of a ray of light that passesthrough the lens in accordance with an embodiment of the presentinvention. In particular, FIG. 58 shows when the ray of light startingfrom the light source 203′ enters the concave part 325′, travels to theinside of the lens 300′, and passes through the third surface 330′ inwhich the lens extension part 340′ has not been formed.

The ray of light of FIG. 58 shows a ray of light adjacent to the bottomBS′, that is, the lower part of the lens 300′. In this instance, the rayof light adjacent to the bottom BS′ can be said to be side light LR′.Side light can become a factor to deteriorate quality of a displaydevice. Accordingly, there is a need for a scheme for effectivelysuppressing such side light. The lens extension part 340′ according toan embodiment of the present invention can become a scheme foreffectively changing the path of side light.

FIG. 59 is a diagram showing the path along which a ray of light passingthrough the lens travels in accordance with an embodiment of the presentinvention. In particular, FIG. 59 shows the state in which a ray oflight starting from the light source 203′ enters the concave part 325′,travels to the inside of the lens 300′, and passes through the thirdsurface V330′ in which the lens extension part 340′ has been formed.

In FIG. 59, the third surface V330′ having the lens extension part 340′formed therein has been indicated by a dotted line. There is no changein a medium with respect to the third surface V330′ having the lensextension part 340′ formed therein because the third surface V330′having the lens extension part 340′ formed therein is a virtual surface.Accordingly, a ray of light LR′ that passes through the third surfaceV330′ having the lens extension part 340′ formed therein may enter thelens extension part 340′ without any change.

As shown in FIG. 59, the lens extension part 340′ may include anextended lower surface 341′, an extended upper surface 345′, and anextended side surface 347′. The extended lower surface 341′ can beparallel to the bottom BS′. The extended lower surface 341′ can beconnected to the second surface 320′. That is, the extended lowersurface 341′ can be disposed at the same height as the second surface320′ or the bottom BS′ in the Z axis.

The extended upper surface 345′ may face the extended lower surface341′. The extended upper surface 345′ can be connected to the thirdsurface 330′. The extended upper surface 345′, together with theextended lower surface 341′, may restrict the thickness (the Z axis) ofthe lens extension part 340′.

The extended side surface 347′ connects the extended lower surface 341′and the extended upper surface 345′. The extended side surface 347′ canbe outward inclined from the boundary of the extended upper surface 345′and the extended side surface 347′ to the second surface 320′. That is,as shown in FIG. 59, the extended side surface 347′ may have a directionextended toward the X axis as it is directed toward the Z axis.

Side light LR′ that has entered the lens extension part 340′ may reachthe extended upper surface 345′. The extended upper surface 345′ can besubstantially parallel to the bottom BS′ or can be formed to have asmall angle. Accordingly, an incident angle between the side light LR′that has reached the extended upper surface 345′ and the extended uppersurface 345′ can be small. In this instance, the incident angle is anangle formed by a ray of light and the boundary of different media whenthe ray of light is incident on the media. The incident angle can be anangle formed by the normal line of the boundary and the ray of light.

That is, an angle at which the side light LR′ is incident on theextended upper surface 345′ can be smaller than an angle (hereinafterreferred to as a “threshold angle”) obtained by taking an arcsinfunction in a reciprocal number of the refractive index of the lens300′. In this instance, the outside of the lens 300′ is air, and therefractive index of air can be considered to be substantially the sameas that of vacuum and can be 1. For example, if the lens 300′ is made ofglass, a threshold angle can be approximately 40 degrees. Accordingly,an angle at which the side light LR′ is incident on the extended uppersurface 345′ can be greater than a threshold angle. That is, the sidelight LR′ incident on the extended upper surface 345′ can be subjectedto total reflection by the extended upper surface 345′.

The side light LR′ reflected by the extended upper surface 345′ maytravel to the extended side surface 347′. The extended side surface 347′may have a direction extended in the positive X axis and the positive Zaxis. That is, the side light LR′ that travels toward the extended sidesurface 347′ may have a large incident angle to the extended sidesurface 347′.

Accordingly, the side light LR′ traveling toward the extended sidesurface 347′ can be subjected to total reflection by the extended sidesurface 347′. In other words, a geometric structure of the extended sidesurface 347′ having the direction extended in the positive X axis andthe positive Z axis may have an influence on the total reflection of theside light LR′ toward the extended side surface 347′.

The side light LR′ that enters the inside of the lens 300′ through theconcave part 325′ travels adjacent to the bottom BS′ before it reachesthe extended upper surface 345′. Accordingly, the side light LR′ thatenters the inside of the lens 300′ through the concave part 325′ mayhave a larger portion in the speed of an X-axis component than in thespeed of a Z-axis component. The side light LR′ that enters the insideof the lens 300′ through the concave part 325′ can be continuouslysubjected to total reflection by the extended upper surface 345′ and theextended side surface 347′.

The path of the side light LR′ can be changed while the side light LR′is continuously reflected by the extended upper surface 345′ and theextended side surface 347′ as described above. The path along which theside light LR′ travels has been chiefly the X-axis direction, but thepath of the ray of light changed by continuous reflection can be chieflythe Z-axis direction. That is, the side light LR′ may have substantiallythe same direction as light chiefly radiated by the lens 300′ due to thestructure of the extended side surface 347′.

FIG. 60 is a diagram showing the path along which a ray of light passingthrough the lens travels in accordance with another embodiment of thepresent invention. FIG. 60 shows the state in which a ray of lightstarting from the light source 203′ enters the concave part 325′,travels to the inside of the lens 300′, and passes through the thirdsurface V330′ having the lens extension part 340′ formed therein.

In FIG. 60, the third surface V330′ having the lens extension part 340′formed therein has been indicated by a dotted line. There is no changein a medium with respect to the third surface V330′ having the lensextension part 340′ formed therein because the third surface V330′having the lens extension part 340′ formed therein is a virtual surface.Accordingly, a ray of light LR′ that passes through the third surfaceV330′ having the lens extension part 340′ formed therein enters the lensextension part 340′ without any change. Side light LR′ that has enteredthe lens extension part 340′ can be incident on the extended uppersurface 345′ and subjected to total reflection. The ray of light LR′reflected by the extended upper surface 345′ may travel toward theextended side surface 347′.

The extended side surface 347′ can be convex toward the second surface320′. Since the extended side surface 347′ has a shape convex toward thesecond surface 320′, at least part of the ray of light LR′ incident onthe extended side surface 347′ can be subjected to total reflection.That is, the major path of the side light LR′ can become the Z axis dueto the structure of the extended side surface 347′.

FIG. 61 is a diagram showing the path along which a ray of light passingthrough the lens travels in accordance with yet another embodiment ofthe present invention. FIG. 61 shows the state in which a ray of lightstarting from the light source 203′ enters the concave part 325′,travels to the inside of the lens 300′, and passes through the thirdsurface V330′ having the lens extension part 340′ formed therein.

In FIG. 61, the third surface V330′ having the lens extension part 340′formed therein has been indicated by a dotted line. There is no changein a medium with respect to the third surface V330′ having the lensextension part 340′ formed therein because the third surface V330′having the lens extension part 340′ formed therein is a virtual surface.Accordingly, a ray of light LR′ that passes through the third surfaceV330′ having the lens extension part 340′ formed therein may enter thelens extension part 340′ without any change.

The extended upper surface 345′ may include the straight-line part 345L′of the extended upper surface and the curved-line part 345C′ of theextended upper surface. The curved-line part 345C′ of the extended uppersurface can be convex toward the second surface 320′. The curved-linepart 345C′ of the extended upper surface connects the third surface 330′and the straight-line part 345L′ of the extended upper surface. Thethird surface V330′ having the lens extension part 340′ formed thereincan be divided into a part V330L′ neighboring the second surface 320′and the remaining part V330U′ by a virtual extension line 345LE′ inwhich the straight-line part 345L′ of the extended upper surface hasbeen extended toward the third surface V330′.

The area of the third surface V330′ having the lens extension part 340′formed therein is divided as follows. An area corresponding to the partV330L′ neighboring the second surface 320′ can be said to be ‘LVR’, andan area corresponding to the remaining part V330U′ can be said to be‘UVR’.

If the curved-line part 345C′ of the extended upper surface has not beenformed, the range of the third surface V330′ having the lens extensionpart 340′ formed therein can be reduced by the area UVR. If thecurved-line part 345C′ of the extended upper surface has not beenformed, side light LR′ incident on the area UVR may outward travelwithout being reflected because it has a small incident angle to thethird surface 330′. That is, a change in the path along which the sidelight LR′ travels can be very small.

If the curved-line part 345C′ of the extended upper surface has beenformed, the side light LR′ incident on the area UVR can be incident onthe extended upper surface 345′. The side light LR′ incident on theextended upper surface 345′ can be subjected to total reflection. Theside light LR′ reflected by the extended upper surface 345′ may traveltoward the extended side surface 347′ or the extended lower surface341′. That is, the path along which the side light LR′ travels can beeffectively changed by a geometric structure of the extended uppersurface.

FIG. 62 is a diagram showing an extended lower surface of the lensextension part according to an embodiment of the present invention. FIG.62 is a diagram of the lens extension part 340′ view from the bottom.The extended lower surface 341′ may include a first extended lowersurface line 342′ forming a boundary along with the second surface 320′.The first extended lower surface line 342′ can be a virtual boundary.The width of the extended lower surface 341′ can be outward narrowed.

Accordingly, the area of the extended lower surface 341′ can becomesmall with respect to the area of the boundary of the lens extensionpart 340′ and the third surface 330′. That is, pressure applied to thelens extension part 340′ can be effectively transferred to the body ofthe lens 300′ through the third surface 330′.

FIG. 63 is a diagram showing an extended lower surface of the lensextension part according to an embodiment of the present invention. Inparticular, FIG. 63 is a diagram of the lens extension part 340′ viewedfrom the bottom.

The extended lower surface 341′ may include a second extended lowersurface line 343′ facing the first extended lower surface line 342′. Thesecond extended lower surface line 343′ can be spaced apart from thefirst extended lower surface line 342′ at a specific interval.Accordingly, pressure applied to the lens extension part 340′ can beeffectively distributed to the extended lower surface 341′.

FIG. 64 is a diagram showing an extended lower surface of the lensextension part according to an embodiment of the present invention. FIG.64 is a diagram of the lens extension part 340′ viewed from the bottom.The second extended lower surface line 343′, together with the firstextended lower surface line 342′, may share the center of a circular arcwhile maintaining a specific interval from the first extended lowersurface line 342′. That is, if the center of the circular arc of thefirst and the second extended lower surface lines 342′ and 343′ is ‘O’,the light source is located at the center ‘O’ and thus a ray oftraveling light can be taken into consideration. In this instance, a rayof light passing through the first extended lower surface line 342′ cantravel toward the second extended lower surface line 343′ withoutoutward traveling. Accordingly, the path along which side light travelscan be effectively changed.

FIG. 65 is a diagram showing an extended lower surface of the lensextension part according to an embodiment of the present invention. FIG.65 is a diagram of the lens extension part 340′ viewed from the bottom.The second extended lower surface line 343′ can be shorter than thefirst extended lower surface line 342′. In this instance, the area ofthe extended lower surface 341′ can become small with respect to thearea of the boundary of the lens extension part 340′ and the thirdsurface 330′. In other words, the width of the lens extension part 340′can be expressed as being smaller toward the outer side. In other words,the length of the Y direction can be expressed as being smaller as thedistance in the X direction becomes distant. This can be applied if agreat force is to be applied to the reflection sheet 126′ of a smallarea.

FIGS. 66 to 69 are diagrams showing the lens installed on the substrateaccording to some embodiments of the present invention. In FIGS. 66 to69, a plurality of the lens extension parts 340′ can be formed. FIGS. 66to 69 are diagrams of the upper part viewed from the lower part of thelens 300′.

As shown in FIG. 66, according to an embodiment of the presentinvention, a plurality of the lens extension parts 340′ can be formed.The plurality of lens extension parts 340′ can be identical. At leastone of the lens extension parts 340′ can be used to set right theorientation of the lens 300′ installed on the substrate 122′. At leastone of the lens extension parts 340′ can closely attach the reflectionsheet 126′ to the frame.

As shown in FIG. 67, according to an embodiment of the presentinvention, four lens extension parts 340′ can be formed. The four lensextension parts 340′ can be classified into two groups. The four lensextension parts 340′ can be classified into lens extension parts 340B′facing each other in the X axis and lens extension parts 340A′ facingeach other in the Y axis. At least one of the lens extension parts 340B′facing each other in the X axis can be used to set right the orientationof the lens 300′ installed on the substrate 122′. At least one of thelens extension parts 340B′ facing each other in the X axis can closelyattach the reflection sheet 126′, laid on the substrate 122′, to thesubstrate 122′. The lens extension parts 340A′ facing each other in theY axis can closely attach the reflection sheet 126′ to the frame 130′.The lens extension parts 340B′ facing each other in the X axis and thelens extension parts 340A′ facing each other in the Y axis can beidentical or different.

As shown in FIG. 68, according to an embodiment of the presentinvention, four lens extension parts 340′ can be formed. The four lensextension parts 340′ can be divided into two groups. The four lensextension parts 340′ can be classified into lens extension parts 340B′facing each other in the X axis and lens extension parts 340A′ facingeach other in the Y axis. The width of the extended lower surface 341′of the lens extension parts 340A′ facing each other in the Y axis can begreater than the width of the extended lower surface 341′ of the lensextension parts 340B′ facing each other in the X axis.

The lens extension parts 340A′ facing each other in the Y axis maydirectly closely attach the reflection sheet 126′ to the frame 130′, orthe lens extension parts 340B′ facing each other in the X axis canclosely attach the reflection sheet 126′ to the frame 130′ by closelyattaching the reflection sheet 126′ to the substrate 122′. That is, thelens 300′ of FIG. 68 according to an embodiment of the present inventionhas a structure in which the reflection sheet 126′ is directly closelyattached to the frame 130′.

As shown in FIG. 69, according to an embodiment of the presentinvention, four lens extension parts 340′ can be formed. The four lensextension parts 340′ can be classified into two groups. The four lensextension parts 340′ can be classified into lens extension parts 340B′facing each other in the X axis and lens extension parts 340A′ and 340C′facing each other in the Y axis. The lens extension parts 340A′ and340C′ facing each other in the Y axis can be classified in the X axis.The plurality of lens extension part 340′ shown in FIG. 69 can bedivided adjacent to the first long side LE1′ or the second long sideLE2′. That is, the area in which the lens 300′ of FIG. 69 according toan embodiment of the present invention comes into contact with thereflection sheet 126′ can be wide, and a ratio of side light whose pathis changed in the lens 300′ of FIG. 69 can be high. The lens extensionparts 340B′ facing each other in the X axis and the lens extension parts340A′ and 340C′ facing each other in the Y axis may have differentheights as described above. Accordingly, the reflection sheet 126′ mayhave a difference in the height at the boundary of the lens extensionparts 340′.

The foregoing embodiments are merely examples and are not to beconsidered as limiting the present disclosure. The present teachings canbe readily applied to other types of methods and apparatuses. Thefeatures, structures, methods, and other characteristics of theembodiments described herein can be combined in various ways to obtainadditional and/or alternative embodiments.

Certain embodiments or other embodiments of the invention describedabove are not mutually exclusive or distinct from each other. Any or allelements of the embodiments of the invention described above can becombined or combined with each other in configuration or function.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the scope of the principles of thisdisclosure. More particularly, various variations and modifications arepossible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

What is claimed is:
 1. A backlight unit, comprising: a frame having abottom area and a sidewall area extended from the bottom area; asubstrate located on the bottom area of the frame; a reflection sheetlocated on the substrate and having a hole; a light source located onthe substrate and disposed in the hole; a lens located on the lightsource and comprising a first surface, a second surface forming a bottomsurface of the lens and facing the first surface, a third surfaceconnecting the first surface and the second surface; and a plurality oflens extension parts extended outwardly from the third surface, whereinthe plurality of lens extension parts comprises at least one first lensextension part that overlaps at least a portion of the reflection sheet,wherein a bottom surface of the at least one first lens extension partis substantially the same level as the second surface of the lens,wherein the second surface of the lens comprises a concave part facingthe light source, wherein a mounting part of the second surfaceprotrudes from the second surface between the concave part and theplurality of lens extension parts, and wherein a height of the mountingpart is smaller than a height of the at least one first lens extensionpart.
 2. The backlight unit of claim 1, wherein the at least one firstlens extension part protrudes outward from the substrate.
 3. Thebacklight unit of claim 1, wherein at least a portion of the lensprotrudes outward from the substrate.
 4. The backlight unit of claim 1,wherein a diameter of the lens is different depending on a location onthe lens.
 5. The backlight unit of claim 1, wherein the reflection sheetcomprises: a first sheet area corresponding to the bottom area of theframe; and a second sheet area corresponding to the sidewall area of theframe, and wherein the second sheet area comprises a dot area configuredto reduce an amount of reflected light.
 6. The backlight unit of claim1, wherein the substrate comprises a substrate groove, and wherein themounting part of the lens is fixed to the substrate groove.
 7. Thebacklight unit of claim 2, wherein the plurality of lens extension partsfurther comprises at least one second lens extension part that overlapsthe substrate.
 8. The backlight unit of claim 4, wherein a shape of thelens is oval.
 9. The backlight unit of claim 7, wherein a height of thesecond lens extension part is greater than the height of the mountingpart.
 10. The backlight unit of claim 7, wherein a distance from thesecond surface of the lens to the at least one first lens extension partis different than a distance from the second surface of the lens to thesecond lens extension part.
 11. The backlight unit of claim 7, whereinshapes of the at least one first lens extension part and the second lensextension part are different from each other.
 12. A display device,comprising: a display panel; a frame positioned at a back of the displaypanel and having a bottom area and a sidewall area extended from thebottom area; a substrate located on the bottom area of the frame; areflection sheet located on the substrate and having a hole; a lightsource located on the substrate and disposed in the hole; a lens locatedon the light source and comprising a first surface, a second surfaceforming a bottom surface of the lens and facing the first surface, athird surface connecting the first surface and the second surface; and aplurality of lens extension parts extended outwardly from the thirdsurface, wherein the plurality of lens extension parts comprise at leastone first lens extension part that overlaps at least a portion of thereflection sheet, wherein a bottom surface of the at least one firstlens extension part is substantially the same level as the secondsurface of the lens, wherein the second surface of the lens comprises aconcave part facing the light source, wherein a mounting part of thesecond surface protrudes from the second surface between the concavepart and the plurality of lens extension parts, and wherein a height ofthe mounting part is less than a height of the at least one first lensextension part.
 13. The display device of claim 12, wherein the at leastone first lens extension part protrudes outward from the substrate. 14.The display device of claim 12, wherein at least a portion of the lensprotrudes outward from the substrate.
 15. The display device of claim12, wherein a diameter of the lens is different depending on a locationon the lens.
 16. The display device of claim 12, wherein the reflectionsheet comprises: a first sheet area corresponding to the bottom area ofthe frame; and a second sheet area corresponding to the sidewall area ofthe frame, and wherein the second sheet area comprises a dot areaconfigured to reduce an amount of reflected light.
 17. The displaydevice of claim 12, wherein the substrate comprises a substrate groove,and wherein the mounting part is fixed to the substrate groove.
 18. Thedisplay device of claim 13, wherein the plurality of lens extensionparts comprise at least one second lens extension part that overlaps thesubstrate.
 19. The display device of claim 15, wherein a shape of thelens is oval.
 20. The display device of claim 18, wherein a height ofthe second lens extension part is greater than the height of themounting part.
 21. The display device of claim 18, wherein a distancefrom the second surface of the lens to the at least one first lensextension part is different than a distance from the second surface ofthe lens to the second lens extension part.
 22. The display device ofclaim 18, wherein shapes of the at least one first lens extension partand the second lens extension part are different from each other.